WorldWideScience

Sample records for chlorinated silicon nitride

  1. Silicon nitride nanosieve membrane

    NARCIS (Netherlands)

    Tong, D.H.; Jansen, Henricus V.; Gadgil, V.J.; Bostan, C.G.; Berenschot, Johan W.; van Rijn, C.J.M.; Elwenspoek, Michael Curt

    2004-01-01

    An array of very uniform cylindrical nanopores with a pore diameter as small as 25 nm has been fabricated in an ultrathin micromachined silicon nitride membrane using focused ion beam (FIB) etching. The pore size of this nanosieve membrane was further reduced to below 10 nm by coating it with

  2. Reaction-bonded silicon nitride

    International Nuclear Information System (INIS)

    Porz, F.

    1982-10-01

    Reaction-bonded silicon nitride (RBSN) has been characterized. The oxidation behaviour in air up to 1500 0 C and 3000 h and the effects of static and cyclic oxidation on room-temperature strength have been studied. (orig./IHOE) [de

  3. Silicon nitride-fabrication, forming and properties

    International Nuclear Information System (INIS)

    Yehezkel, O.

    1983-01-01

    This article, which is a literature survey of the recent years, includes description of several methods for the formation of silicone nitride, and five methods of forming: Reaction-bonded silicon nitride, sintering, hot pressing, hot isostatic pressing and chemical vapour deposition. Herein are also included data about mechanical and physical properties of silicon nitride and the relationship between the forming method and the properties. (author)

  4. Kinetic modelling of chlorination of nitrided ilmenite using MATLAB

    Energy Technology Data Exchange (ETDEWEB)

    Ramakrishnan, Sivakumar, E-mail: srsivakumar@usm.my; Kwok, Teong Chen, E-mail: ctck@live.com; Hamid, Sheikh Abdul Rezan Sheikh Abdul, E-mail: rezanshk@gmail.com [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300, Nibong Tebal, Penang (Malaysia)

    2016-07-19

    In the present study, chlorination of nitride ilmenite using 2{sup k} factorial design was investigated. The reduction experiments were carried out in a temperature range of 400°C to 500°C, chlorination duration from 1 hour to 3 hours and using different type of carbon reactant. Phases of raw materials and reduced samples were analyzed by X-ray diffraction (XRD). Ilmenite was reduced to TiO{sub x}C{sub y}N{sub z} through carbothermal and nitridation for further chlorination into titanium tetrachloride. The Design of Experiment analysis suggested that the types of carbon reactant contribute most influence to the extent of chlorination of nitride ilmenite. The extent of chlorination was highest at 500°C with 3 hours chlorination time and carbon nanotube as carbon reactant.

  5. Waveguide silicon nitride grating coupler

    Science.gov (United States)

    Litvik, Jan; Dolnak, Ivan; Dado, Milan

    2016-12-01

    Grating couplers are one of the most used elements for coupling of light between optical fibers and photonic integrated components. Silicon-on-insulator platform provides strong confinement of light and allows high integration. In this work, using simulations we have designed a broadband silicon nitride surface grating coupler. The Fourier-eigenmode expansion and finite difference time domain methods are utilized in design optimization of grating coupler structure. The fully, single etch step grating coupler is based on a standard silicon-on-insulator wafer with 0.55 μm waveguide Si3N4 layer. The optimized structure at 1550 nm wavelength yields a peak coupling efficiency -2.6635 dB (54.16%) with a 1-dB bandwidth up to 80 nm. It is promising way for low-cost fabrication using complementary metal-oxide- semiconductor fabrication process.

  6. Fusion bonding of silicon nitride surfaces

    DEFF Research Database (Denmark)

    Reck, Kasper; Østergaard, Christian; Thomsen, Erik Vilain

    2011-01-01

    While silicon nitride surfaces are widely used in many micro electrical mechanical system devices, e.g. for chemical passivation, electrical isolation or environmental protection, studies on fusion bonding of two silicon nitride surfaces (Si3N4–Si3N4 bonding) are very few and highly application...

  7. Colloidal characterization of ultrafine silicon carbide and silicon nitride powders

    Science.gov (United States)

    Whitman, Pamela K.; Feke, Donald L.

    1986-01-01

    The effects of various powder treatment strategies on the colloid chemistry of aqueous dispersions of silicon carbide and silicon nitride are examined using a surface titration methodology. Pretreatments are used to differentiate between the true surface chemistry of the powders and artifacts resulting from exposure history. Silicon nitride powders require more extensive pretreatment to reveal consistent surface chemistry than do silicon carbide powders. As measured by titration, the degree of proton adsorption from the suspending fluid by pretreated silicon nitride and silicon carbide powders can both be made similar to that of silica.

  8. High temperature corrosion of silicon carbide and silicon nitride in the presence of chloride compound

    International Nuclear Information System (INIS)

    McNallan, M.

    1993-01-01

    Silicon carbide and silicon nitride are resistant to oxidation because a protective silicon dioxide films on their surfaces in most oxidizing environments. Chloride compounds can attack the surface in two ways: 1) chlorine can attack the silicon directly to form a volatile silicon chloride compound or 2) alkali compounds combined with the chlorine can be transported to the surface where they flux the silica layer by forming stable alkali silicates. Alkali halides have enough vapor pressure that a sufficient quantity of alkali species to cause accelerated corrosion can be transported to the ceramic surface without the formation of a chloride deposit. When silicon carbide is attacked simultaneously by chlorine and oxygen, the corrosion products include both volatile and condensed spices. Silicon nitride is much more resistance to this type of attack than silicon carbide. Silicon based ceramics are exposed to oxidizing gases in the presence of alkali chloride vapors, the rate of corrosion is controlled primarily by the driving force for the formation of alkali silicate, which can be quantified as the activity of the alkali oxide in equilibrium with the corrosive gas mixture. In a gas mixture containing a fixed partial pressure of KCl, the rate of corrosion is accelerated by increasing the concentration of water vapor and inhibited by increasing the concentration of HCl. Similar results have been obtained for mixtures containing other alkalis and halogens. (Orig./A.B.)

  9. Compressive creep of silicon nitride

    International Nuclear Information System (INIS)

    Silva, C.R.M. da; Melo, F.C.L. de; Cairo, C.A.; Piorino Neto, F.

    1990-01-01

    Silicon nitride samples were formed by pressureless sintering process, using neodymium oxide and a mixture of neodymium oxide and yttrio oxide as sintering aids. The short term compressive creep behaviour was evaluated over a stress range of 50-300 MPa and temperature range 1200 - 1350 0 C. Post-sintering heat treatments in nitrogen with a stepwise decremental variation of temperature were performed in some samples and microstructural analysis by X-ray diffraction and transmission electron microscopy showed that the secondary crystalline phase which form from the remnant glass are dependent upon composition and percentage of aditives. Stress exponent values near to unity were obtained for materials with low glass content suggesting grain boundary diffusion accommodation processes. Cavitation will thereby become prevalent with increase in stress, temperature and decrease in the degree of crystallization of the grain boundary phase. (author) [pt

  10. Low temperature anodic bonding to silicon nitride

    DEFF Research Database (Denmark)

    Weichel, Steen; Reus, Roger De; Bouaidat, Salim

    2000-01-01

    Low-temperature anodic bonding to stoichiometric silicon nitride surfaces has been performed in the temperature range from 3508C to 4008C. It is shown that the bonding is improved considerably if the nitride surfaces are either oxidized or exposed to an oxygen plasma prior to the bonding. Both bu...

  11. Preparation of aluminum nitride-silicon carbide nanocomposite powder by the nitridation of aluminum silicon carbide

    NARCIS (Netherlands)

    Itatani, K.; Tsukamoto, R.; Delsing, A.C.A.; Hintzen, H.T.J.M.; Okada, I.

    2002-01-01

    Aluminum nitride (AlN)-silicon carbide (SiC) nanocomposite powders were prepared by the nitridation of aluminum-silicon carbide (Al4SiC4) with the specific surface area of 15.5 m2·g-1. The powders nitrided at and above 1400°C for 3 h contained the 2H-phases which consisted of AlN-rich and SiC-rich

  12. Evanescent field phase shifting in a silicon nitride waveguide using a coupled silicon slab

    DEFF Research Database (Denmark)

    Jensen, Asger Sellerup; Oxenløwe, Leif Katsuo; Green, William M. J.

    2015-01-01

    An approach for electrical modulation of low-loss silicon nitride waveguides is proposed, using a silicon nitride waveguide evanescently loaded with a thin silicon slab. The thermooptic phase-shift characteristics are investigated in a racetrack resonator configuration....

  13. Indentation fatigue in silicon nitride, alumina and silicon carbide ...

    Indian Academy of Sciences (India)

    Repeated indentation fatigue (RIF) experiments conducted on the same spot of different structural ceramics viz. a hot pressed silicon nitride (HPSN), sintered alumina of two different grain sizes viz. 1 m and 25 m, and a sintered silicon carbide (SSiC) are reported. The RIF experiments were conducted using a Vicker's ...

  14. Microstructure and mechanical properties of silicon nitride structural ceramics of silicon nitride

    International Nuclear Information System (INIS)

    Strohaecker, T.R.; Nobrega, M.C.S.

    1989-01-01

    The utilization of direct evaluation technic of tenacity for fracturing by hardness impact in silicon nitride ceramics is described. The microstructure were analysied, by Scanning Electron Microscopy, equiped with a microanalysis acessory by X ray energy dispersion. The difference between the values of K IC measure for two silicon nitride ceramics is discussed, in function of the microstructures and the fracture surfaces of the samples studied. (C.G.C.) [pt

  15. Covalent biofunctionalization of silicon nitride surfaces

    NARCIS (Netherlands)

    Arafat, A.; Giesbers, M.; Rosso, M.; Sudhölter, E.J.R.; Schroën, C.G.P.H.; White, R.G.; Li Yang,; Linford, M.R.; Zuilhof, H.

    2007-01-01

    Covalently attached organic monolayers on etched silicon nitride (SixN4; x 3) surfaces were prepared by reaction of SixN4-coated wafers with neat or solutions of 1-alkenes and 1-alkynes in refluxing mesitylene. The surface modification was monitored by measurement of the static water contact angle,

  16. Colloidal characterization of silicon nitride and silicon carbide

    Science.gov (United States)

    Feke, Donald L.

    1986-01-01

    The colloidal behavior of aqueous ceramic slips strongly affects the forming and sintering behavior and the ultimate mechanical strength of the final ceramic product. The colloidal behavior of these materials, which is dominated by electrical interactions between the particles, is complex due to the strong interaction of the solids with the processing fluids. A surface titration methodology, modified to account for this interaction, was developed and used to provide fundamental insights into the interfacial chemistry of these systems. Various powder pretreatment strategies were explored to differentiate between true surface chemistry and artifacts due to exposure history. The colloidal behavior of both silicon nitride and carbide is dominated by silanol groups on the powder surfaces. However, the colloid chemistry of silicon nitride is apparently influenced by an additional amine group. With the proper powder treatments, silicon nitride and carbide powder can be made to appear colloidally equivalent. The impact of these results on processing control will be discussed.

  17. Atomic-layer deposition of silicon nitride

    CERN Document Server

    Yokoyama, S; Ooba, K

    1999-01-01

    Atomic-layer deposition (ALD) of silicon nitride has been investigated by means of plasma ALD in which a NH sub 3 plasma is used, catalytic ALD in which NH sub 3 is dissociated by thermal catalytic reaction on a W filament, and temperature-controlled ALD in which only a thermal reaction on the substrate is employed. The NH sub 3 and the silicon source gases (SiH sub 2 Cl sub 2 or SiCl sub 4) were alternately supplied. For all these methods, the film thickness per cycle was saturated at a certain value for a wide range of deposition conditions. In the catalytic ALD, the selective deposition of silicon nitride on hydrogen-terminated Si was achieved, but, it was limited to only a thin (2SiO (evaporative).

  18. Photoluminescence and electrical properties of silicon oxide and silicon nitride superlattices containing silicon nanocrystals

    International Nuclear Information System (INIS)

    Shuleiko, D V; Ilin, A S

    2016-01-01

    Photoluminescence and electrical properties of superlattices with thin (1 to 5 nm) alternating silicon-rich silicon oxide or silicon-rich silicon nitride, and silicon oxide or silicon nitride layers containing silicon nanocrystals prepared by plasma-enhanced chemical vapor deposition with subsequent annealing were investigated. The entirely silicon oxide based superlattices demonstrated photoluminescence peak shift due to quantum confinement effect. Electrical measurements showed the hysteresis effect in the vicinity of zero voltage due to structural features of the superlattices from SiOa 93 /Si 3 N 4 and SiN 0 . 8 /Si 3 N 4 layers. The entirely silicon nitride based samples demonstrated resistive switching effect, comprising an abrupt conductivity change at about 5 to 6 V with current-voltage characteristic hysteresis. The samples also demonstrated efficient photoluminescence with maximum at ∼1.4 eV, due to exiton recombination in silicon nanocrystals. (paper)

  19. Indentation fatigue in silicon nitride, alumina and silicon carbide ...

    Indian Academy of Sciences (India)

    Unknown

    carbide ceramics. A K MUKHOPADHYAY. Central Glass and Ceramic Research Institute, Kolkata 700 032, India. Abstract. Repeated indentation fatigue (RIF) experiments conducted on the same spot of different structural ceramics viz. a hot pressed silicon nitride (HPSN), sintered alumina of two different grain sizes viz.

  20. Ion beam induces nitridation of silicon

    International Nuclear Information System (INIS)

    Petravic, M.; Williams, J.S.; Conway, M.

    1998-01-01

    High dose ion bombardment of silicon with reactive species, such as oxygen and nitrogen, has attracted considerable interest due to possible applications of beam-induced chemical compounds with silicon. For example, high energy oxygen bombardment of Si is now routinely used to form buried oxide layers for device purposes, the so called SIMOX structures. On the other hand, Si nitrides, formed by low energy ( 100 keV) nitrogen beam bombardment of Si, are attractive as oxidation barriers or gate insulators, primarily due to the low diffusivity of many species in Si nitrides. However, little data exists on silicon nitride formation during bombardment and its angle dependence, in particular for N 2 + bombardment in the 10 keV range, which is of interest for analytical techniques such as SIMS. In SIMS, low energy oxygen ions are more commonly used as bombarding species, as oxygen provides stable ion yields and enhances the positive secondary ion yield. Therefore, a large body of data can be found in the literature on oxide formation during low energy oxygen bombardment. Nitrogen bombardment of Si may cause similar effects to oxygen bombardment, as nitrogen and oxygen have similar masses and ranges in Si, show similar sputtering effects and both have the ability to form chemical compounds with Si. In this work we explore this possibility in some detail. We compare oxide and nitride formation during oxygen and nitrogen ion bombardment of Si under similar conditions. Despite the expected similar behaviour, some large differences in compound formation were found. These differences are explained in terms of different atomic diffusivities in oxides and nitrides, film structural differences and thermodynamic properties. (author)

  1. Silicon Nitride Antireflection Coatings for Photovoltaic Cells

    Science.gov (United States)

    Johnson, C.; Wydeven, T.; Donohoe, K.

    1984-01-01

    Chemical-vapor deposition adapted to yield graded index of refraction. Silicon nitride deposited in layers, refractive index of which decreases with distance away from cell/coating interface. Changing index of refraction allows adjustment of spectral transmittance for wavelengths which cell is most effective at converting light to electric current. Average conversion efficiency of solar cells increased from 8.84 percent to 12.63 percent.

  2. Bonding silicon nitride using glass-ceramic

    International Nuclear Information System (INIS)

    Dobedoe, R.S.

    1995-01-01

    Silicon nitride has been successfully bonded to itself using magnesium-aluminosilicate glass and glass-ceramic. For some samples, bonding was achieved using a diffusion bonder, but in other instances, following an initial degassing hold, higher temperatures were used in a nitrogen atmosphere with no applied load. For diffusion bonding, a small applied pressure at a temperature below which crystallisation occurs resulted in intimate contact. At slightly higher temperatures, the extent of the reaction at the interface and the microstructure of the glass-ceramic joint was highly sensitive to the bonding temperature. Bonding in a nitrogen atmosphere resulted in a solution-reprecipitation reaction. A thin layer of glass produced a ''dry'', glass-free joint, whilst a thicker layer resulted in a continuous glassy join across the interface. The chromium silicide impurities within the silicon nitride react with the nucleating agent in the glass ceramic, which may lead to difficulty in producing a fine glass-ceramic microstructure. Slightly lower temperatures in nitrogen resulted in a polycrystalline join but the interfacial contact was poor. It is hoped that one of the bonds produced may be developed to eventually form part of a graded joint between silicon nitride and a high temperature nickel alloy. (orig.)

  3. Vertical integration of high-Q silicon nitride microresonators into silicon-on-insulator platform.

    Science.gov (United States)

    Li, Qing; Eftekhar, Ali A; Sodagar, Majid; Xia, Zhixuan; Atabaki, Amir H; Adibi, Ali

    2013-07-29

    We demonstrate a vertical integration of high-Q silicon nitride microresonators into the silicon-on-insulator platform for applications at the telecommunication wavelengths. Low-loss silicon nitride films with a thickness of 400 nm are successfully grown, enabling compact silicon nitride microresonators with ultra-high intrinsic Qs (~ 6 × 10(6) for 60 μm radius and ~ 2 × 10(7) for 240 μm radius). The coupling between the silicon nitride microresonator and the underneath silicon waveguide is based on evanescent coupling with silicon dioxide as buffer. Selective coupling to a desired radial mode of the silicon nitride microresonator is also achievable using a pulley coupling scheme. In this work, a 60-μm-radius silicon nitride microresonator has been successfully integrated into the silicon-on-insulator platform, showing a single-mode operation with an intrinsic Q of 2 × 10(6).

  4. The Effect of Polymer Char on Nitridation Kinetics of Silicon

    Science.gov (United States)

    Chan, Rickmond C.; Bhatt, Ramakrishna T.

    1994-01-01

    Effects of polymer char on nitridation kinetics of attrition milled silicon powder have been investigated from 1200 to 1350 C. Results indicate that at and above 1250 C, the silicon compacts containing 3.5 wt percent polymer char were fully converted to Si3N4 after 24 hr exposure in nitrogen. In contrast, the silicon compacts without polymer char could not be fully converted to Si3N4 at 1350 C under similar exposure conditions. At 1250 and 1350 C, the silicon compacts with polymer char showed faster nitridation kinetics than those without the polymer char. As the polymer char content is increased, the amount of SiC in the nitrided material is also increased. By adding small amounts (approx. 2.5 wt percent) of NiO, the silicon compacts containing polymer char can be completely nitrided at 1200 C. The probable mechanism for the accelerated nitridation of silicon containing polymer char is discussed.

  5. Four-Wave Mixing in Silicon-Rich Nitride Waveguides

    DEFF Research Database (Denmark)

    Mitrovic, Miranda; Guan, Xiaowei; Ji, Hua

    2015-01-01

    We demonstrate four-wave mixing wavelength conversion in silicon-rich nitride waveguides which are a promising alternative to silicon for nonlinear applications. The obtained conversion efficiency reaches -13.6 dB while showing no significant nonlinear loss.......We demonstrate four-wave mixing wavelength conversion in silicon-rich nitride waveguides which are a promising alternative to silicon for nonlinear applications. The obtained conversion efficiency reaches -13.6 dB while showing no significant nonlinear loss....

  6. Compositional analysis of silicon oxide/silicon nitride thin films

    Directory of Open Access Journals (Sweden)

    Meziani Samir

    2016-06-01

    Full Text Available Hydrogen, amorphous silicon nitride (SiNx:H abbreviated SiNx films were grown on multicrystalline silicon (mc-Si substrate by plasma enhanced chemical vapour deposition (PECVD in parallel configuration using NH3/SiH4 gas mixtures. The mc-Si wafers were taken from the same column of Si cast ingot. After the deposition process, the layers were oxidized (thermal oxidation in dry oxygen ambient environment at 950 °C to get oxide/nitride (ON structure. Secondary ion mass spectroscopy (SIMS, Rutherford backscattering spectroscopy (RBS, Auger electron spectroscopy (AES and energy dispersive X-ray analysis (EDX were employed for analyzing quantitatively the chemical composition and stoichiometry in the oxide-nitride stacked films. The effect of annealing temperature on the chemical composition of ON structure has been investigated. Some species, O, N, Si were redistributed in this structure during the thermal oxidation of SiNx. Indeed, oxygen diffused to the nitride layer into Si2O2N during dry oxidation.

  7. Fabrication of functional structures on thin silicon nitride membranes

    NARCIS (Netherlands)

    Ekkels, P.; Tjerkstra, R.W.; Krijnen, Gijsbertus J.M.; Berenschot, Johan W.; Brugger, J.P.; Elwenspoek, Michael Curt

    A process to fabricate functional polysilicon structures above large (4×4 mm2) thin (200 nm), very flat LPCVD silicon rich nitride membranes was developed. Key features of this fabrication process are the use of low-stress LPCVD silicon nitride, sacrificial layer etching, and minimization of

  8. Analytical and Experimental Evaluation of Joining Silicon Carbide to Silicon Carbide and Silicon Nitride to Silicon Nitride for Advanced Heat Engine Applications Phase II

    Energy Technology Data Exchange (ETDEWEB)

    Sundberg, G.J.

    1994-01-01

    Techniques were developed to produce reliable silicon nitride to silicon nitride (NCX-5101) curved joins which were used to manufacture spin test specimens as a proof of concept to simulate parts such as a simple rotor. Specimens were machined from the curved joins to measure the following properties of the join interlayer: tensile strength, shear strength, 22 C flexure strength and 1370 C flexure strength. In parallel, extensive silicon nitride tensile creep evaluation of planar butt joins provided a sufficient data base to develop models with accurate predictive capability for different geometries. Analytical models applied satisfactorily to the silicon nitride joins were Norton's Law for creep strain, a modified Norton's Law internal variable model and the Monkman-Grant relationship for failure modeling. The Theta Projection method was less successful. Attempts were also made to develop planar butt joins of siliconized silicon carbide (NT230).

  9. Method of production of hollow silicon nitride articles

    International Nuclear Information System (INIS)

    Parr, N.L.; Brown, R.L.

    1971-01-01

    The hollow articles prepared according to the invention have a high density, exhibit no internal stresses and correspond to high demands of tolerance and surface quality. One obtains these by flame spraying silicon powder on a pre-heated form designed with separating agent - e.g. NaCl. After removing the form, the silicon is nitridated to silicon nitride by heating in N 2 or in an atmosphere of ammonia. This process can be interrupted if the article is also to be mechanically processed, and then the nitridation can be completed. (Hoe/LH) [de

  10. A review of oxide, silicon nitride, and silicon carbide brazing

    International Nuclear Information System (INIS)

    Santella, M.L.; Moorhead, A.J.

    1987-01-01

    There is growing interest in using ceramics for structural applications, many of which require the fabrication of components with complicated shapes. Normal ceramic processing methods restrict the shapes into which these materials can be produced, but ceramic joining technology can be used to overcome many of these limitations, and also offers the possibility for improving the reliability of ceramic components. One method of joining ceramics is by brazing. The metallic alloys used for bonding must wet and adhere to the ceramic surfaces without excessive reaction. Alumina, partially stabilized zirconia, and silicon nitride have high ionic character to their chemical bonds and are difficult to wet. Alloys for brazing these materials must be formulated to overcome this problem. Silicon carbide, which has some metallic characteristics, reacts excessively with many alloys, and forms joints of low mechanical strength. The brazing characteristics of these three types of ceramics, and residual stresses in ceramic-to-metal joints are briefly discussed

  11. Optimization of time–temperature schedule for nitridation of silicon ...

    Indian Academy of Sciences (India)

    pact was optimized by kinetic study of the reaction, 3Si + 2N2 = Si3N4 at four different temperatures (1250°C,. 1300°C, 1350°C and 1400°C). ... Reaction sintered silicon nitride; nitridation; reaction kinetics. 1. Introduction. Formation of ..... cation of silica layer resulted in active oxidation of silicon at high temperature to ...

  12. Optical property of silicon quantum dots embedded in silicon nitride by thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Baek Hyun, E-mail: bhkim@andrew.cmu.ed [Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, United Sates (United States); Davis, Robert F. [Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, United Sates (United States); Park, Seong-Ju [Nanophotonic Semiconductors Laboratory, Department of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 500-712 (Korea, Republic of)

    2010-01-01

    We present the effects on the thermal annealing of silicon quantum dots (Si QDs) embedded in silicon nitride. The improved photoluminescence (PL) intensities and the red-shifted PL spectra were obtained with annealing treatment in the range of 700 to 1000 {sup o}C. The shifts of PL spectra were attributed to the increase in the size of Si QDs. The improvement of the PL intensities was also attributed to the reduction of point defects at Si QD/silicon nitride interface and in the silicon nitride due to hydrogen passivation effects.

  13. Gelcasting of SiC/Si for preparation of silicon nitride bonded silicon carbide

    International Nuclear Information System (INIS)

    Xie, Z.P.; Tsinghua University, Beijing,; Cheng, Y.B.; Lu, J.W.; Huang, Y.

    2000-01-01

    In the present paper, gelcasting of aqueous slurry with coarse silicon carbide(1mm) and fine silicon particles was investigated to fabricate silicon nitride bonded silicon carbide materials. Through the examination of influence of different polyelectrolytes on the Zeta potential and viscosity of silicon and silicon carbide suspensions, a stable SiC/Si suspension with 60 vol% solid loading could be prepared by using polyelectrolyte of D3005 and sodium alginate. Gelation of this suspension can complete in 10-30 min at 60-80 deg C after cast into mold. After demolded, the wet green body can be dried directly in furnace and the green strength will develop during drying. Complex shape parts with near net size were prepared by the process. Effects of the debindering process on nitridation and density of silicon nitride bonded silicon carbide were also examined. Copyright (2000) The Australian Ceramic Society

  14. Second-harmonic generation in substoichiometric silicon nitride layers

    Science.gov (United States)

    Pecora, Emanuele; Capretti, Antonio; Miano, Giovanni; Dal Negro, Luca

    2013-03-01

    Harmonic generation in optical circuits offers the possibility to integrate wavelength converters, light amplifiers, lasers, and multiple optical signal processing devices with electronic components. Bulk silicon has a negligible second-order nonlinear optical susceptibility owing to its crystal centrosymmetry. Silicon nitride has its place in the microelectronic industry as an insulator and chemical barrier. In this work, we propose to take advantage of silicon excess in silicon nitride to increase the Second Harmonic Generation (SHG) efficiency. Thin films have been grown by reactive magnetron sputtering and their nonlinear optical properties have been studied by femtosecond pumping over a wide range of excitation wavelengths, silicon nitride stoichiometry and thermal processes. We demonstrate SHG in the visible range (375 - 450 nm) using a tunable 150 fs Ti:sapphire laser, and we optimize the SH emission at a silicon excess of 46 at.% demonstrating a maximum SHG efficiency of 4x10-6 in optimized films. Polarization properties, generation efficiency, and the second order nonlinear optical susceptibility are measured for all the investigated samples and discussed in terms of an effective theoretical model. Our findings show that the large nonlinear optical response demonstrated in optimized Si-rich silicon nitride materials can be utilized for the engineering of nonlinear optical functions and devices on a Si chip.

  15. Cavitation contributes substantially to tensile creep in silicon nitride

    International Nuclear Information System (INIS)

    Luecke, W.E.; Wiederhorn, S.M.; Hockey, B.J.; Krause, R.F. Jr.; Long, G.G.

    1995-01-01

    During tensile creep of a hot isostatically pressed (HIPed) silicon nitride, the volume fraction of cavities increases linearly with strain; these cavities produce nearly all of the measured strain. In contrast, compressive creep in the same stress and temperature range produces very little cavitation. A stress exponent that increases with stress (var-epsilon ∝ σ n , 2 < n < 7) characterizes the tensile creep response, while the compressive creep response exhibits a stress dependence of unity. Furthermore, under the same stress and temperature, the material creeps nearly 100 times faster in tension than in compression. Transmission electron microscopy (TEM) indicates that the cavities formed during tensile creep occur in pockets of residual crystalline silicate phase located at silicon nitride multigrain junctions. Small-angle X-ray scattering (SAXS) from crept material quantifies the size distribution of cavities observed in TEM and demonstrates that cavity addition, rather than cavity growth, dominates the cavitation process. These observations are in accord with a model for creep based on the deformation of granular materials in which the microstructure must dilate for individual grains t slide past one another. During tensile creep the silicon nitride grains remain rigid; cavitation in the multigrain junctions allows the silicate to flow from cavities to surrounding silicate pockets, allowing the dilation of the microstructure and deformation of the material. Silicon nitride grain boundary sliding accommodates this expansion and leads to extension of the specimen. In compression, where cavitation is suppressed, deformation occurs by solution-reprecipitation of silicon nitride

  16. Memory characteristics of silicon nitride with silicon nanocrystals as a charge trapping layer of nonvolatile memory devices

    International Nuclear Information System (INIS)

    Choi, Sangmoo; Yang, Hyundeok; Chang, Man; Baek, Sungkweon; Hwang, Hyunsang; Jeon, Sanghun; Kim, Juhyung; Kim, Chungwoo

    2005-01-01

    Silicon nitride with silicon nanocrystals formed by low-energy silicon plasma immersion ion implantation has been investigated as a charge trapping layer of a polycrystalline silicon-oxide-nitride-oxide-silicon-type nonvolatile memory device. Compared with the control sample without silicon nanocrystals, silicon nitride with silicon nanocrystals provides excellent memory characteristics, such as larger width of capacitance-voltage hysteresis, higher program/erase speed, and lower charge loss rate at elevated temperature. These improved memory characteristics are derived by incorporation of silicon nanocrystals into the charge trapping layer as additional accessible charge traps with a deeper effective trap energy level

  17. Origin of interfacial charging in irradiated silicon nitride capacitors

    International Nuclear Information System (INIS)

    Hughes, R.C.

    1984-01-01

    Many experiments show that when metal-silicon nitride-silicon dioxide-silicon (MNOS) devices are irradiated in short circuit, a large interfacial charge builds up near the nitride-SiO 2 -Si interface. This effect cannot be explained by simple models of radiation-induced conductivity of the nitride, but it is reported here that inclusion of carrier diffusion and recombination in the photoconductivity equations can predict the observed behavior. Numerical solutions on a computer are required, however, when these complications are added. The simulations account for the magnitude and radiation dose dependence of the results, as well as the occurrence of a steady state during the irradiation. The location of the excess trapped charge near the interface is also predicted, along with the large number of new traps which must be introduced to influence the steady-state charge distribution

  18. Nano-ridge fabrication by local oxidation of silicon edges with silicon nitride as a mask

    NARCIS (Netherlands)

    Haneveld, J.; Berenschot, Johan W.; Maury, P.A.; Jansen, Henricus V.

    2005-01-01

    A method to fabricate nano-ridges over a full wafer is presented. The fabrication method uses local oxidation of silicon, with silicon nitride as a mask, and wet anisotropic etching of silicon. The realized structures are 7-20 nm wide, 40-100 nm high and centimeters long. All dimensions are easily

  19. Silicon nitride photonics: from visible to mid-infrared wavelengths

    Science.gov (United States)

    Micó, Gloria; Bru, Luis A.; Pastor, Daniel; Doménech, David; Fernández, Juan; Sánchez, Ana; Cirera, Josep M.; Domínguez, Carlos; Muñoz, Pascual

    2018-02-01

    Silicon nitride has received a lot of attention during the last ten years, for applications such as bio-photonics, tele/datacom, optical signal processing and sensing. In this paper, firstly an updated review of the state of the art of silicon nitride photonics integration platforms will be provided. Secondly, our developments on a moderate confinement Si3N4 platform in the near-infrared will be presented. Finally, our steps towards establishing a Si3N4 based platform for broadband operation spanning from visible to mid-infrared wavelengths will be introduced.

  20. The oxidation of titanium nitride- and silicon nitride-coated stainless steel in carbon dioxide environments

    International Nuclear Information System (INIS)

    Mitchell, D.R.G.; Stott, F.H.

    1992-01-01

    A study has been undertaken into the effects of thin titanium nitride and silicon nitride coatings, deposited by physical vapour deposition and chemical vapour deposition processes, on the oxidation resistance of 321 stainless steel in a simulated advanced gas-cooled reactor carbon dioxide environment for long periods at 550 o C and 700 o C under thermal-cycling conditions. The uncoated steel contains sufficient chromium to develop a slow-growing chromium-rich oxide layer at these temperatures, particularly if the surfaces have been machine-abraded. Failure of this layer in service allows formation of less protective iron oxide-rich scales. The presence of a thin (3-4 μm) titanium nitride coating is not very effective in increasing the oxidation resistance since the ensuing titanium oxide scale is not a good barrier to diffusion. Even at 550 o C, iron oxide-rich nodules are able to develop following relatively rapid oxidation and breakdown of the coating. At 700 o C, the coated specimens oxidize at relatively similar rates to the uncoated steel. A thin silicon nitride coating gives improved oxidation resistance, with both the coating and its slow-growing oxide being relatively electrically insulating. The particular silicon nitride coating studied here was susceptible to spallation on thermal cycling, due to an inherently weak coating/substrate interface. (Author)

  1. Damage initiation and evolution in silicon nitride under\

    Czech Academy of Sciences Publication Activity Database

    Raga, R.; Khader, I.; Chlup, Zdeněk; Kailer, A.

    360-361, AUG (2016), s. 147-159 ISSN 0043-1648 EU Projects: European Commission(XE) 263476 - ROLICER Institutional support: RVO:68081723 Keywords : Silicon nitride * Rollingcontactfatigue * Subsurface damage Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.531, year: 2016

  2. Hardness and thermal stability of cubic silicon nitride

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Kragh, Flemming; Frost, D. J.

    2001-01-01

    The hardness and thermal stability of cubic spinel silicon nitride (c-Si3N4), synthesized under high-pressure and high-temperature conditions, have been studied by microindentation measurements, and x-ray powder diffraction and scanning electron microscopy, respectively The phase at ambient...

  3. TXRF analysis of trace metals in thin silicon nitride films

    International Nuclear Information System (INIS)

    Vereecke, G.; Arnauts, S.; Verstraeten, K.; Schaekers, M.; Heyrts, M.M.

    2000-01-01

    As critical dimensions of integrated circuits continue to decrease, high dielectric constant materials such as silicon nitride are being considered to replace silicon dioxide in capacitors and transistors. The achievement of low levels of metal contamination in these layers is critical for high performance and reliability. Existing methods of quantitative analysis of trace metals in silicon nitride require high amounts of sample (from about 0.1 to 1 g, compared to a mass of 0.2 mg for a 2 nm thick film on a 8'' silicon wafer), and involve digestion steps not applicable to films on wafers or non-standard techniques such as neutron activation analysis. A novel approach has recently been developed to analyze trace metals in thin films with analytical techniques currently used in the semiconductor industry. Sample preparation consists of three steps: (1) decomposition of the silicon nitride matrix by moist HF condensed at the wafer surface to form ammonium fluosilicate. (2) vaporization of the fluosilicate by a short heat treatment at 300 o C. (3) collection of contaminants by scanning the wafer surface with a solution droplet (VPD-DSC procedure). The determination of trace metals is performed by drying the droplet on the wafer and by analyzing the residue by TXRF, as it offers the advantages of multi-elemental analysis with no dilution of the sample. The lower limits of detection for metals in 2 nm thick films on 8'' silicon wafers range from about 10 to 200 ng/g. The present study will focus on the matrix effects and the possible loss of analyte associated with the evaporation of the fluosilicate salt, in relation with the accuracy and the reproducibility of the method. The benefits of using an internal standard will be assessed. Results will be presented from both model samples (ammonium fluoride contaminated with metallic salts) and real samples (silicon nitride films from a production tool). (author)

  4. Silicon oxide nanoimprint stamp fabrication by edge lithography reinforced with silicon nitride

    NARCIS (Netherlands)

    Zhao, Yiping; Berenschot, Johan W.; de Boer, Meint J.; Jansen, Henricus V.; Tas, Niels Roelof; Huskens, Jurriaan; Elwenspoek, Michael Curt

    2007-01-01

    The fabrication of silicon oxide nanoimprint stamp employing edge lithography in combination with silicon nitride deposition is presented. The fabrication process is based on conventional photolithography an weg etching methods. Nanoridges with width dimension of sub-20 nm were fabricated by edge

  5. Fabrication of a silicon oxide stamp by edge lithography reinforced with silicon nitride for nanoimprint lithography

    NARCIS (Netherlands)

    Zhao, Yiping; Berenschot, Johan W.; de Boer, M.; de Boer, Meint J.; Jansen, Henricus V.; Tas, Niels Roelof; Huskens, Jurriaan; Elwenspoek, Michael Curt

    2008-01-01

    The fabrication of a stamp reinforced with silicon nitride is presented for its use in nanoimprint lithography. The fabrication process is based on edge lithography using conventional optical lithography and wet anisotropic etching of 110 silicon wafers. SiO2 nano-ridges of 20 nm in width were

  6. Amorphous silicon rich silicon nitride optical waveguides for high density integrated optics

    DEFF Research Database (Denmark)

    Philipp, Hugh T.; Andersen, Karin Nordström; Svendsen, Winnie Edith

    2004-01-01

    Amorphous silicon rich silicon nitride optical waveguides clad in silica are presented as a high-index contrast platform for high density integrated optics. Performance of different cross-sectional geometries have been measured and are presented with regards to bending loss and insertion loss...

  7. Modification of silicon nitride and silicon carbide surfaces for food and biosensor applications

    NARCIS (Netherlands)

    Rosso, M.

    2009-01-01

    Silicon-rich silicon nitride (SixN4, x > 3) is a robust insulating material widely used for the coating of microdevices: its high chemical and mechanical inertness make it a material of choice for the reinforcement of fragile microstructures (e.g. suspended microcantilevers, micro-fabricated

  8. Thin film silicon on silicon nitride for radiation hardened dielectrically isolated MISFET's

    International Nuclear Information System (INIS)

    Neamen, D.; Shedd, W.; Buchanan, B.

    1975-01-01

    The permanent ionizing radiation effects resulting from charge trapping in a silicon nitride isolation dielectric have been determined for a total ionizing dose up to 10 7 rads (Si). Junction FET's, whose active channel region is directly adjacent to the silicon-silicon nitride interface, were used to measure the effects of the radiation induced charge trapping in the Si 3 N 4 isolation dielectric. The JFET saturation current and channel conductance versus junction gate voltage and substrate voltage were characterized as a function of the total ionizing radiation dose. The experimental results on the Si 3 N 4 are compared to results on similar devices with SiO 2 dielectric isolation. The ramifications of using the silicon nitride for fabricating radiation hardened dielectrically isolated MIS devices are discussed

  9. Analytical and experimental evaluation of joining silicon carbide to silicon carbide and silicon nitride to silicon nitride for advanced heat engine applications Phase 2. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Sundberg, G.J.; Vartabedian, A.M.; Wade, J.A.; White, C.S. [Norton Co., Northboro, MA (United States). Advanced Ceramics Div.

    1994-10-01

    The purpose of joining, Phase 2 was to develop joining technologies for HIP`ed Si{sub 3}N{sub 4} with 4wt% Y{sub 2}O{sub 3} (NCX-5101) and for a siliconized SiC (NT230) for various geometries including: butt joins, curved joins and shaft to disk joins. In addition, more extensive mechanical characterization of silicon nitride joins to enhance the predictive capabilities of the analytical/numerical models for structural components in advanced heat engines was provided. Mechanical evaluation were performed by: flexure strength at 22 C and 1,370 C, stress rupture at 1,370 C, high temperature creep, 22 C tensile testing and spin tests. While the silicon nitride joins were produced with sufficient integrity for many applications, the lower join strength would limit its use in the more severe structural applications. Thus, the silicon carbide join quality was deemed unsatisfactory to advance to more complex, curved geometries. The silicon carbide joining methods covered within this contract, although not entirely successful, have emphasized the need to focus future efforts upon ways to obtain a homogeneous, well sintered parent/join interface prior to siliconization. In conclusion, the improved definition of the silicon carbide joining problem obtained by efforts during this contract have provided avenues for future work that could successfully obtain heat engine quality joins.

  10. Thermodynamics of silicon nitridation - Effect of hydrogen

    Science.gov (United States)

    Shaw, N. J.; Zeleznik, F. J.

    1982-01-01

    Equilibrium compositions for the nitridization of Si were calculated to detect the effectiveness of H2 in removal of the oxide film and in increasing the concentration of SiO and reducing the proportions of O2. Gibbs free energy for the formation of SiN2O was computed above 1685 K, and at lower temperatures. The thermodynamic properties of SiN2O2 were then considered from 1000-3000 K, taking into account the known thermodynamic data for 39 molecular combinations of the Si, Ni, and O. The gases formed were assumed ideal mixtures with pure phase condensed species. The mole fractions were obtained for a system of SiO2 with each Si particle covered with a thin layer of SiO2 before nitridation, and a system in which the nitriding atmosphere had access to the Si. The presence of H2 was determined to enhance the removal of NiO2 in the first system, decrease the partial pressure of O2, increase the partial pressures of SiO, Si, H2O, NH3, and SiH4, while its effects were negligible in the Si system.

  11. High-rate silicon nitride deposition for photovoltaics : from fundamentals to industrial application

    NARCIS (Netherlands)

    Kessels, W.M.M.; Oever, van den P.J.; Bosch, R.C.M.; Bijker, M.D.; Evers, M.F.J.; Schram, D.C.; Sanden, van de M.C.M.

    2005-01-01

    The development of a novel plasma technique for high rate (> 1 nm/s) silicon nitride deposition for multifunctional antireflection coatings on crystalline silicon solar cells is described. The research has involved the analysis of the structural and optical properties of the silicon nitride films as

  12. High-rate silicon nitride deposition for photovoltaics : from fundamentals to industrial application

    NARCIS (Netherlands)

    Kessels, W.M.M.; Oever, van den P.J.; Bosch, R.C.M.; Bijker, M.D.; Evers, M.F.J.; Schram, D.C.; Sanden, van de M.C.M.

    2004-01-01

    The development of a novel plasma technique for high rate (> 1 nm/s) silicon nitride deposition for multifunctional antireflection coatings on crystalline silicon solar cells is described. The research has involved the analysis of the structural and optical properties of the silicon nitride films as

  13. Some new aspects of microstructural development during sintering of silicon nitride

    International Nuclear Information System (INIS)

    Feuer, H.; Woetting, G.; Gugel, E.

    1994-01-01

    The mechanical properties of silicon nitride ceramics strongly depend on their microstructure. However, there is still a lively discussion about the parameters controlling the microstructural development. The current research was stimulated by the observation that a bimodal grain-size distribution in dense silicon nitride has a very beneficial effect on the mechanical properties, especially on the fracture toughness. This paper is focused on the relationship between the α-β-transformation and the densification of silicon nitride powders with different characteristics and sintering additives. Effects of β-grains originally present in the silicon nitride powder, of added β-silicon nitride seeds and of β-crystals formed by the α/β-transformation on the resulting microstructure and on the properties are discussed. The results are summarised in a model describing prerequisites and processing conditions, which are necessary to achieve a bimodal microstructure, i. e. a self-reinforced silicon nitride ceramic. (orig.)

  14. Silicon Nitride Photonic Integration Platforms for Visible, Near-Infrared and Mid-Infrared Applications

    Science.gov (United States)

    Micó, Gloria; Pastor, Daniel; Pérez, Daniel; Doménech, José David; Fernández, Juan; Baños, Rocío; Alemany, Rubén; Sánchez, Ana M.; Cirera, Josep M.; Mas, Roser

    2017-01-01

    Silicon nitride photonics is on the rise owing to the broadband nature of the material, allowing applications of biophotonics, tele/datacom, optical signal processing and sensing, from visible, through near to mid-infrared wavelengths. In this paper, a review of the state of the art of silicon nitride strip waveguide platforms is provided, alongside the experimental results on the development of a versatile 300 nm guiding film height silicon nitride platform. PMID:28895906

  15. SONOS memories with embedded silicon nanocrystals in nitride

    International Nuclear Information System (INIS)

    Liu, Mei-Chun; Chiang, Tsung-Yu; Chao, Tien-Sheng; Kuo, Po-Yi; Lei, Tan-Fu; Chou, Ming-Hong; Wu, Yi-Hong; Cheng, Ching-Hwa; Liu, Sheng-Hsien; Yang, Wen-Luh; You, Hsin-Chiang

    2008-01-01

    We have successfully demonstrated SONOS memories with embedded Si-NCs in silicon nitride. This new structure exhibits excellent characteristics in terms of larger memory windows and longer retention time compared to control devices. Using the same thickness 2.5 nm of the bottom tunneling oxide, we found that N 2 O is better than O 2 oxide. Retention property is improved when the thickness of N 2 O is increased to 3.0 nm

  16. Niobium nitride Josephson junctions with silicon and germanium barriers

    International Nuclear Information System (INIS)

    Cukauskas, E.J.; Carter, W.L.

    1988-01-01

    Niobium nitride based junctions with silicon, germanium, and composite silicon/germanium barriers were fabricated and characterized for several barrier compositions. The current-voltage characteristics were analyzed at several temperatures using the Simmons model and numerical integration of the WKB approximation for the average barrier height and effective thickness. The zero voltage conductance was measured from 1.5 K to 300 K and compared to the Mott hopping conductivity model and the Stratton tunneling temperature dependence. Conductivity followed Mott conductivity at temperatures above 60 K for junctions with less than 100 angstrom thick barriers

  17. Corrosion of silicon nitride in high temperature alkaline solutions

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Liyan, E-mail: liyan.qiu@cnl.ca; Guzonas, Dave A.; Qian, Jing

    2016-08-01

    The corrosion of silicon nitride (Si{sub 3}N{sub 4}) in alkaline solutions was studied at temperatures from 60 to 300 °C. Si{sub 3}N{sub 4} experienced significant corrosion above 100 °C. The release rates of silicon and nitrogen follow zero order reaction kinetics and increase with increasing temperature. The molar ratio of dissolved silicon and nitrogen species in the high temperature solutions is the same as that in the solid phase (congruent dissolution). The activation energy for silicon and nitrogen release rates is 75 kJ/mol which agrees well with that of silica dissolution. At 300 °C, the release of aluminum is observed and follows first order reaction kinetics while other minor constituents including Ti and Y are highly enriched on the corrosion films due to the low solubility of their oxides.

  18. Hydrogen diffusion between plasma-deposited silicon nitride-polyimide polymer interfaces

    International Nuclear Information System (INIS)

    Nguyen, S.V.; Kerbaugh, M.

    1988-01-01

    This paper reports a nuclear reaction analysis (NRA) for hydrogen technique used to analyze the hydrogen concentration near plasma enhanced chemical vapor deposition (PECVD) silicon nitride-polyimide interfaces at various nitride-deposition and polyimide-polymer-curing temperatures. The CF 4 + O 2 (8% O 2 ) plasma-etch-rate variation of PECVD silicon nitride films deposited on polyimide appeared to correlate well with the variation of hydrogen-depth profiles in the nitride films. The NRA data indicate that hydrogen-depth-profile fluctuation in the nitride films is due to hydrogen diffusion between the nitride-polyimide interfaces during deposition. Annealing treatment of polyimide films in a hydrogen atmosphere prior to the nitride film deposition tends to enhance the hydrogen-depth-profile uniformity in the nitride films, and thus substantially reduces or eliminates variation in the nitride plasma-etch rate

  19. Frequency effects and properties of plasma deposited fluorinated silicon nitride

    International Nuclear Information System (INIS)

    Chang, C.; Flamm, D.L.; Ibbotson, D.E.; Mucha, J.A.

    1988-01-01

    The properties of low-hydrogen, fluorinated plasma-enhanced chemical vapor deposition (PECVD) silicon nitride films grown using NF 3 /SiH 4 /N 2 feed mixtures in 200 kHz and 14 MHz discharges were compared. High-energy ion bombardment at 200 kHz is expected to enhance surface diffusion and chemical reconstruction. Compared to fluorinated silicon nitride deposited at 14 MHz under otherwise comparable conditions, the 200 kHz films had a lower Si--H bond concentration (approx. 21 cm -3 ), lower total hydrogen content (5--8 x 10 21 cm -3 ), better resistance to oxidation, lower compressive stress (-0.7 to -1.5 Gdyne/cm), and higher density (3.1 g/cm 3 ). The dielectric constant of better low-frequency Class I films was constant to 500 MHz, while that of high-frequency films fell up to 15% between 100 Hz and 10 MHz. The absorption edges of low-frequency PECVD fluorinated silicon nitride films were between 5.0 and 6.1 eV, which compare with 4.4 to 5.6 eV for the high-excitation frequency fluorinated material and 3 to 4 eV for conventional PECVD nitride. However high-frequency films may have fewer trap centers and a lower dielectric constant. 14 MHz p-SiN:F films grown with NH 3 as an auxiliary nitrogen source showed absorption edges similar to low-frequency material grown from NF 3 /SiH 4 /N 2 , but they have substantially more N--H bonding. The dielectric constant and absorption edge of these films were comparable to those of low-frequency p-SiN:F from NF 3 /SiH 4 /N 2

  20. Thermogravimetric analysis of silicon carbide-silicon nitride fibers at ambient to 1000 C in air

    Science.gov (United States)

    Daniels, J. G.; Ledbetter, F. E., III; Clemons, J. M.; Penn, B. G.

    1984-01-01

    Thermogravimetric analysis of silicon carbide-silicon nitride fibers was carried out at ambient to 1000 C in air. The weight loss over this temperature range was negligible. In addition, the oxidative stability at high temperature for a short period of time was determined. Fibers heated at 1000 C in air for fifteen minutes showed negligible weight loss (i.e., less than 1 percent).

  1. Increased carrier lifetimes in epitaxial silicon layers on buried silicon nitride produced by ion implantation

    International Nuclear Information System (INIS)

    Skorupa, W.; Kreissig, U.; Hensel, E.; Bartsch, H.

    1984-01-01

    Carrier lifetimes were measured in epitaxial silicon layers deposited on buried silicon nitride produced by high-dose nitrogen implantation at 330 keV. The values were in the range 20-200 μs. The results are remarkable taking into account the high density of crystal defects in the epitaxial layers. Comparing with other SOI technologies the measured lifetimes are higher by 1-2 orders of magnitude. (author)

  2. Thermo-Optic Characterization of Silicon Nitride Resonators for Cryogenic Photonic Circuits

    NARCIS (Netherlands)

    Elshaari, A.W.A.; Esmaeil Zadeh, I.; Jöns, K.D.; Zwiller, Val

    2016-01-01

    In this paper, we characterize the Thermo-optic properties of silicon nitride ring resonators between 18 and 300 K. The Thermo-optic coefficients of the silicon nitride core and the oxide cladding are measured by studying the temperature dependence of the resonance wavelengths. The resonant modes

  3. Hydrogen concentration profiles and chemical bonding in silicon nitride

    International Nuclear Information System (INIS)

    Peercy, P.S.; Stein, H.J.; Doyle, B.L.; Picraux, S.T.

    1978-01-01

    The complementary technique of nuclear reaction analysis and infrared absorption were used to study the concentration profile and chemical bonding of hydrogen in silicon nitride for different preparation and annealing conditions. Silicon nitride prepared by chemical vapor deposition from ammonia-silane mixtures is shown to have hydrogen concentrations of 8.1 and 6.5 at.% for deposition temperatures of 750 and 900 0 C, respectively. Plasma deposition at 300 0 C from these gases results in hydrogen concentrations of approximately 22 at.%. Comparison of nuclear reaction analysis and infrared absorption measurements after isothermal annealing shows that all of the hydrogen retained in the films remains bonded to either silicon or nitrogen and that hydrogen release from the material on annealing is governed by various trap energies involving at least two N-H and one Si-H trap. Reasonable estimates of the hydrogen release rates can be made from the effective diffusion coefficient obtained from measurements of hydrogen migration in hydrogen implanted and annealed films

  4. Influence of the initial grain size of silicon on microstructure and mechanical properties of reaction-sintered silicon nitride

    International Nuclear Information System (INIS)

    Heinrich, J.

    1977-01-01

    The influence of the initial grain size of the silicon powder on the microstructure and the resulting mechanical properties are studied. The smaller the grain size of the silicon powders used, the higher will be the degree of reaction at the beginning of the nitridation reaction and the higher the amount of α-modification in the fully nitridated samples. Moreover, the nitrification time can be considerably shortened when fine-grained silicon powders ( [de

  5. Combination of silicon nitride and porous silicon induced optoelectronic features enhancement of multicrystalline silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Rabha, Mohamed Ben; Dimassi, Wissem; Gaidi, Mounir; Ezzaouia, Hatem; Bessais, Brahim [Laboratoire de Photovoltaique, Centre de Recherches et des Technologies de l' Energie, Technopole de Borj-Cedria, BP 95, 2050 Hammam-Lif (Tunisia)

    2011-06-15

    The effects of antireflection (ARC) and surface passivation films on optoelectronic features of multicrystalline silicon (mc-Si) were investigated in order to perform high efficiency solar cells. A double layer consisting of Plasma Enhanced Chemical Vapor Deposition (PECVD) of silicon nitride (SiN{sub x}) on porous silicon (PS) was achieved on mc-Si surfaces. It was found that this treatment decreases the total surface reflectivity from about 25% to around 6% in the 450-1100 nm wavelength range. As a result, the effective minority carrier diffusion length, estimated from the Laser-beam-induced current (LBIC) method, was found to increase from 312 {mu}m for PS-treated cells to about 798 {mu}m for SiN{sub x}/PS-treated ones. The deposition of SiN{sub x} was found to impressively enhance the minority carrier diffusion length probably due to hydrogen passivation of surface, grain boundaries and bulk defects. Fourier Transform Infrared Spectroscopy (FTIR) shows that the vibration modes of the highly suitable passivating Si-H bonds exhibit frequency shifts toward higher wavenumber, depending on the x ratio of the introduced N atoms neighbors. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Tensile creep behavior in an advanced silicon nitride

    International Nuclear Information System (INIS)

    Lofaj, F.

    2000-01-01

    Tensile creep behavior and changes in the microstructure of the advanced silicon nitride, SN 88M, were studied at temperatures from 1250 to 1400 C to reveal the creep resistance and lifetime-controlling processes. Assuming power law dependence of the minimum strain rate on stress, stress exponents from 6 to 8 and an apparent activation energy of 780 kJ/mol were obtained. Extensive electron microscopy observations revealed significant changes in the crystalline secondary phases and creep damage development. Creep damage was classified in two groups: 'inter-granular' defects in the amorphous boundary phases, and 'intra-granular' defects in silicon nitride grains. The inter-granular defects involved multigrain junction cavities, two-grain junction cavities, microcracks and cracks. The intra-granular defects included broken large grains, small symmetrical and asymmetrical cavities, and crack-like intragranular cavities. Cavities are generated continuously during the whole deformation starting from the threshold strain of ∝0.1%, and they contribute linearly to the tensile strain. Cavities produce more than 90% of the total tensile strain, and it is concluded that cavitation is the main creep mechanism in silicon nitride ceramics. The multigrain junction cavities are considered to be the most important for generating new volume and producing tensile strain. The Luecke and Wiederhorn (L and W) creep model, based on cavitation at multigrain junctions according to an exponential law, was proven to correspond to the stress dependence of the minimum strain rate. A qualitative model based on the L and W model was suggested and expanded to include intragranular cavitation. The basic mechanisms involve a repeating of the sequence grain boundary sliding (GBS) => cavitation at multigrain junctions => viscous flow and dissolution-precipitation. (orig.)

  7. Nanostructured silicon nitride from wheat and rice husks

    Energy Technology Data Exchange (ETDEWEB)

    Qadri, S. B.; Rath, B. B.; Gorzkowski, E. P.; Wollmershauser, J. A.; Feng, C. R. [Materials Science and Component Technology Directorate, Naval Research Laboratory, Washington, D.C. 20375 (United States)

    2016-04-07

    Nanoparticles, submicron-diameter tubes, and rods of Si{sub 3}N{sub 4} were synthesized from the thermal treatment of wheat and rice husks at temperatures at and above 1300 °C in a nitrogen atmosphere. The whole pattern Rietveld analysis of the observed diffraction data from treatments at 1300 °C showed the formation of only hexagonal α-phase of Si{sub 3}N{sub 4} with an R-factor of 1%, whereas samples treated at 1400 °C and above showed both α- and β-phases with an R-factor of 2%. Transmission electron microscopy showed the presence of tubes, rods, and nanoparticles of Si{sub 3}N{sub 4}. In a two-step process, where pure SiC was produced first from rice or wheat husk in an argon atmosphere and subsequently treated in a nitrogen atmosphere at 1450 °C, a nanostructured composite material having α- and β-phases of Si{sub 3}N{sub 4} combined with cubic phase of SiC was formed. The thermodynamics of the formation of silicon nitride is discussed in terms of the solid state reaction between organic matter (silica content), which is inherently present in the wheat and rice husks, with the nitrogen from the furnace atmosphere. Nanostructures of silicon nitride formed by a single direct reaction or their composites with SiC formed in a two-step process of agricultural byproducts provide an uncomplicated sustainable synthesis route for silicon nitride used in mechanical, biotechnology, and electro-optic nanotechnology applications.

  8. Surface Area, and Oxidation Effects on Nitridation Kinetics of Silicon Powder Compacts

    Science.gov (United States)

    Bhatt, R. T.; Palczer, A. R.

    1998-01-01

    Commercially available silicon powders were wet-attrition-milled from 2 to 48 hr to achieve surface areas (SA's) ranging from 1.3 to 70 sq m/g. The surface area effects on the nitridation kinetics of silicon powder compacts were determined at 1250 or 1350 C for 4 hr. In addition, the influence of nitridation environment, and preoxidation on nitridation kinetics of a silicon powder of high surface area (approximately equals 63 sq m/g) was investigated. As the surface area increased, so did the percentage nitridation after 4 hr in N2 at 1250 or 1350 C. Silicon powders of high surface area (greater than 40 sq m/g) can be nitrided to greater than 70% at 1250 C in 4 hr. The nitridation kinetics of the high-surface-area powder compacts were significantly delayed by preoxidation treatment. Conversely, the nitridation environment had no significant influence on the nitridation kinetics of the same powder. Impurities present in the starting powder, and those accumulated during attrition milling, appeared to react with the silica layer on the surface of silicon particles to form a molten silicate layer, which provided a path for rapid diffusion of nitrogen and enhanced the nitridation kinetics of high surface area silicon powder.

  9. An Annotated Bibliography on Silicon Nitride for Structural Applications

    Science.gov (United States)

    1977-03-01

    annotated in this bibliography with each entry under the name of the specific author. 16. Canteloup, J., and Mocellin , A., "Synthesis of...thinning. Oxidation of the SJ3N4 grains started at the grain boundaries. 81. Torre, J. P., and Mocellin , A., "On the Existence of Si-AI-O-N Solid...Torre, J. P., and Mocellin , A., "Some Effects of Al and O2 on the Nitridation of Silicon Compacts", J. Mater. Sei., 11., 1725-1733(1976). Highest final

  10. Elastic properties of silicon nitride ceramics reinforced with graphene nanofillers

    Czech Academy of Sciences Publication Activity Database

    Seiner, Hanuš; Ramírez, C.; Koller, M.; Sedlák, Petr; Landa, Michal; Miranzo, P.; Belmonte, M.; Osendí, M. I.

    2015-01-01

    Roč. 87, December (2015), s. 675-680 ISSN 0264-1275 R&D Projects: GA ČR GB14-36566G Institutional support: RVO:61388998 Keywords : multilayer graphene * graphene oxide (GO) * silicon nitride * elastic constants * elastic modulus * shear modulus Subject RIV: JI - Composite Materials Impact factor: 3.997, year: 2015 http://www.sciencedirect.com/science/article/pii/S0264127515302938/pdfft?md5=571e00fd7f976e9b66ed789ae2a868b2&pid=1-s2.0-S0264127515302938-main.pdf

  11. Quality factor improvement of silicon nitride micro string resonators

    DEFF Research Database (Denmark)

    Schmid, Silvan; Malm, Bjarke; Boisen, Anja

    2011-01-01

    Resonant micro and nano strings are of interest for sensor applications due to their extraordinary high quality factors, low mass and tunable resonant frequency. It has been found that the quality factor of strings is usually limited by clamping loss. In this work, clamping loss has been addressed...... by varying the clamping design and string geometry. We present silicon nitride micro strings with quality factors (Q) of up to 4 million in high vacuum achieved by minimizing clamping loss. For applications such as for chemical sensing, strings need to vibrate at atmospheric pressure. Maximal quality factor...

  12. Ultra-compact silicon nitride grating coupler for microscopy systems

    OpenAIRE

    Zhu, Yunpeng; Wang, Jie; Xie, Weiqiang; Tian, Bin; Li, Yanlu; Brainis, Edouard; Jiao, Yuqing; Van Thourhout, Dries

    2017-01-01

    Grating couplers have been widely used for coupling light between photonic chips and optical fibers. For various quantum-optics and bio-optics experiments, on the other hand, there is a need to achieve good light coupling between photonic chips and microscopy systems. Here, we propose an ultra-compact silicon nitride (SiN) grating coupler optimized for coupling light from a waveguide to a microscopy system. The grating coupler is about 4 by 2 mu m(2) in size and a 116 nm 1 dB bandwidth can be...

  13. Oxidation Protection of Porous Reaction-Bonded Silicon Nitride

    Science.gov (United States)

    Fox, D. S.

    1994-01-01

    Oxidation kinetics of both as-fabricated and coated reaction-bonded silicon nitride (RBSN) were studied at 900 and 1000 C with thermogravimetry. Uncoated RBSN exhibited internal oxidation and parabolic kinetics. An amorphous Si-C-O coating provided the greatest degree of protection to oxygen, with a small linear weight loss observed. Linear weight gains were measured on samples with an amorphous Si-N-C coating. Chemically vapor deposited (CVD) Si3N4 coated RBSN exhibited parabolic kinetics, and the coating cracked severely. A continuous-SiC-fiber-reinforced RBSN composite was also coated with the Si-C-O material, but no substantial oxidation protection was observed.

  14. Single-layer graphene on silicon nitride micromembrane resonators

    DEFF Research Database (Denmark)

    Schmid, Silvan; Bagci, Tolga; Zeuthen, Emil

    2014-01-01

    Due to their low mass, high quality factor, and good optical properties, silicon nitride (SiN) micromembrane resonators are widely used in force and mass sensing applications, particularly in optomechanics. The metallization of such membranes would enable an electronic integration with the prospect...... for exciting new devices, such as optoelectromechanical transducers. Here, we add a single-layer graphene on SiN micromembranes and compare electromechanical coupling and mechanical properties to bare dielectric membranes and to membranes metallized with an aluminium layer. The electrostatic coupling...

  15. Compressibility and thermal expansion of cubic silicon nitride

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Lindelov, H.; Gerward, Leif

    2002-01-01

    The compressibility and thermal expansion of the cubic silicon nitride (c-Si3N4) phase have been investigated by performing in situ x-ray powder-diffraction measurements using synchrotron radiation, complemented with computer simulations by means of first-principles calculations. The bulk...... compressibility of the c-Si3N4 phase originates from the average of both Si-N tetrahedral and octahedral compressibilities where the octahedral polyhedra are less compressible than the tetrahedral ones. The origin of the unit cell expansion is revealed to be due to the increase of the octahedral Si-N and N-N bond...

  16. The atomic and electronic structure of amorphous silicon nitride

    International Nuclear Information System (INIS)

    Alvarez, F.; Valladares, A.A.

    2002-01-01

    Using a novel approach to the ab initio generation of random networks we constructed two nearly stoichiometric samples of amorphous silicon nitride with the same content x= 1.29. The two 64-atom periodically-continued cubic diamond-like cells contain 28 silicons and 36 nitrogens randomly substituted, and were amorphized with a 6 f s time step by heating them to just below their melting temperature with a Harris-functional based, molecular dynamics code in the LDA approximation. The averaged total radial distribution function (RDF) obtained is compared with some existing Tersoff-like potential simulations and with experiment; ours agree with experiment. All the partial radial features are calculated and the composition of the second peak also agrees with experiment. The electronic structure is calculated and the optical gaps obtained using both a HOMO-LUMO approach and the Tauc-like procedure developed recently that gives reasonable gaps. (Author)

  17. Vibrational Spectroscopy of Chemical Species in Silicon and Silicon-Rich Nitride Thin Films

    Directory of Open Access Journals (Sweden)

    Kirill O. Bugaev

    2012-01-01

    Full Text Available Vibrational properties of hydrogenated silicon-rich nitride (SiN:H of various stoichiometry (0.6≤≤1.3 and hydrogenated amorphous silicon (a-Si:H films were studied using Raman spectroscopy and Fourier transform infrared spectroscopy. Furnace annealing during 5 hours in Ar ambient at 1130∘C and pulse laser annealing were applied to modify the structure of films. Surprisingly, after annealing with such high-thermal budget, according to the FTIR data, the nearly stoichiometric silicon nitride film contains hydrogen in the form of Si–H bonds. From analysis of the FTIR data of the Si–N bond vibrations, one can conclude that silicon nitride is partly crystallized. According to the Raman data a-Si:H films with hydrogen concentration 15% and lower contain mainly Si–H chemical species, and films with hydrogen concentration 30–35% contain mainly Si–H2 chemical species. Nanosecond pulse laser treatments lead to crystallization of the films and its dehydrogenization.

  18. First-principles study of the effects of halogen dopants on the properties of intergranular films in silicon nitride ceramics

    International Nuclear Information System (INIS)

    Painter, Gayle S.; Becher, Paul F.; Kleebe, H.-J.; Pezzotti, G.

    2002-01-01

    The nanoscale intergranular films that form in the sintering of ceramics often occur as adherent glassy phases separating the crystalline grains in the ceramic. Consequently, the properties of these films are often equal in importance to those of the constituent grains in determining the ceramic's properties. The measured characteristics of the silica-rich phase separating the crystalline grains in Si 3 N 4 and many other ceramics are so reproducible that SiO 2 has become a model system for studies of intergranular films (IGF's). Recently, the influence of fluorine and chlorine dopants in SiO 2 -rich IGF's in silicon nitride was precisely documented by experiment. Along with the expected similarities between the halogens, some dramatically contrasting effects were found. But the atomic-scale mechanisms distinguishing the effects F and Cl on IGF behavior have not been well understood. First-principles density functional calculations reported here provide a quantum-level description of how these dopant-host interactions affect the properties of IGF's, with specific modeling of F and Cl in the silica-rich IGF in silicon nitride. Calculations were carried out for the energetics, structural changes, and forces on the atoms making up a model cluster fragment of an SiO 2 intergranular film segment in silicon nitride with and without dopants. Results show that both anions participate in the breaking of bonds within the IGF, directly reducing the viscosity of the SiO 2 -rich film and promoting decohesion. Observed differences in the way fluorine and chlorine affect IGF behavior become understandable in terms of the relative stabilities of the halogens as they interact with Si atoms that have lost one if their oxygen bridges

  19. Broadband wavelength conversion in hydrogenated amorphous silicon waveguide with silicon nitride layer

    Science.gov (United States)

    Wang, Jiang; Li, Yongfang; Wang, Zhaolu; Han, Jing; Huang, Nan; Liu, Hongjun

    2018-01-01

    Broadband wavelength conversion based on degenerate four-wave mixing is theoretically investigated in a hydrogenated amorphous silicon (a-Si:H) waveguide with silicon nitride inter-cladding layer (a-Si:HN). We have found that enhancement of the non-linear effect of a-Si:H waveguide nitride intermediate layer facilitates broadband wavelength conversion. Conversion bandwidth of 490 nm and conversion efficiency of 11.4 dB were achieved in a numerical simulation of a 4 mm-long a-Si:HN waveguide under 1.55 μm continuous wave pumping. This broadband continuous-wave wavelength converter has potential applications in photonic networks, a type of readily manufactured low-cost highly integrated optical circuits.

  20. Electron and ion beam degradation effects in AES analysis of silicon nitride thin films

    International Nuclear Information System (INIS)

    Fransen, F.; Vanden Berghe, R.; Vlaeminck, R.; Hinoul, M.; Remmerie, J.; Maes, H.E.

    1985-01-01

    Silicon nitride films are currently investigated by AES combined with ion profiling techniques for their stoichiometry and oxygen content. During this analysis, ion beam and primary electron effects were observed. The effect of argon ion bombardment is the preferential sputtering of nitrogen, forming 'covalent' silicon at the surface layer (AES peak at 91 eV). The electron beam irradiation results in a decrease of the covalent silicon peak, either by an electron beam annealing effect in the bulk of the silicon nitride film, or by an ionization enhanced surface diffusion process of the silicon (electromigration). By the electron beam annealing, nitrogen species are liberated in the bulk of the silicon nitride film and migrate towards the surface where they react with the covalent silicon. The ionization enhanced diffusion originates from local charging of the surface, induced by the electron beam. (author)

  1. Demonstration of slot-waveguide structures on silicon nitride / silicon oxide platform.

    Science.gov (United States)

    Barrios, C A; Sánchez, B; Gylfason, K B; Griol, A; Sohlström, H; Holgado, M; Casquel, R

    2007-05-28

    We report on the first demonstration of guiding light in vertical slot-waveguides on silicon nitride/silicon oxide material system. Integrated ring resonators and Fabry-Perot cavities have been fabricated and characterized in order to determine optical features of the slot-waveguides. Group index behavior evidences guiding and confinement in the low-index slot region at O-band (1260-1370nm) telecommunication wavelengths. Propagation losses of <20 dB/cm have been measured for the transverse-electric mode of the slot-waveguides.

  2. Modelling structure and properties of amorphous silicon boron nitride ceramics

    Directory of Open Access Journals (Sweden)

    Johann Christian Schön

    2011-06-01

    Full Text Available Silicon boron nitride is the parent compound of a new class of high-temperature stable amorphous ceramics constituted of silicon, boron, nitrogen, and carbon, featuring a set of properties that is without precedent, and represents a prototypical random network based on chemical bonds of predominantly covalent character. In contrast to many other amorphous materials of technological interest, a-Si3B3N7 is not produced via glass formation, i.e. by quenching from a melt, the reason being that the binary components, BN and Si3N4, melt incongruently under standard conditions. Neither has it been possible to employ sintering of μm-size powders consisting of binary nitrides BN and Si3N4. Instead, one employs the so-called sol-gel route starting from single component precursors such as TADB ((SiCl3NH(BCl2. In order to determine the atomic structure of this material, it has proven necessary to simulate the actual synthesis route.Many of the exciting properties of these ceramics are closely connected to the details of their amorphous structure. To clarify this structure, it is necessary to employ not only experimental probes on many length scales (X-ray, neutron- and electron scattering; complex NMR experiments; IR- and Raman scattering, but also theoretical approaches. These address the actual synthesis route to a-Si3B3N7, the structural properties, the elastic and vibrational properties, aging and coarsening behaviour, thermal conductivity and the metastable phase diagram both for a-Si3B3N7 and possible silicon boron nitride phases with compositions different from Si3N4: BN = 1 : 3. Here, we present a short comprehensive overview over the insights gained using molecular dynamics and Monte Carlo simulations to explore the energy landscape of a-Si3B3N7, model the actual synthesis route and compute static and transport properties of a-Si3BN7.

  3. Single-layer graphene on silicon nitride micromembrane resonators

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, Silvan; Guillermo Villanueva, Luis; Amato, Bartolo; Boisen, Anja [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, Building 345 East, 2800 Kongens Lyngby (Denmark); Bagci, Tolga; Zeuthen, Emil; Sørensen, Anders S.; Usami, Koji; Polzik, Eugene S. [QUANTOP, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Taylor, Jacob M. [Joint Quantum Institute/NIST, College Park, Maryland 20899 (United States); Herring, Patrick K.; Cassidy, Maja C. [School of Engineering and Applied Science, Harvard University, Cambridge, Massachusetts 02138 (United States); Marcus, Charles M. [Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Cheol Shin, Yong; Kong, Jing [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2014-02-07

    Due to their low mass, high quality factor, and good optical properties, silicon nitride (SiN) micromembrane resonators are widely used in force and mass sensing applications, particularly in optomechanics. The metallization of such membranes would enable an electronic integration with the prospect for exciting new devices, such as optoelectromechanical transducers. Here, we add a single-layer graphene on SiN micromembranes and compare electromechanical coupling and mechanical properties to bare dielectric membranes and to membranes metallized with an aluminium layer. The electrostatic coupling of graphene covered membranes is found to be equal to a perfectly conductive membrane, without significantly adding mass, decreasing the superior mechanical quality factor or affecting the optical properties of pure SiN micromembranes. The concept of graphene-SiN resonators allows a broad range of new experiments both in applied physics and fundamental basic research, e.g., for the mechanical, electrical, or optical characterization of graphene.

  4. Optically induced paramagnetism in amorphous hydrogenated silicon nitride thin films

    International Nuclear Information System (INIS)

    Warren, W.L.; Kanicki, J.; Buchwald, W.R.; Rong, F.C.; Harmatz, M.

    1992-01-01

    This paper reports that the creation mechanisms of Si and N dangling bond defect centers in amorphous hydrogenated silicon nitride thin films by ultra-violet (UV) illumination are investigated. The creation efficiency and density of Si centers in the N-rich films are independent of illumination temperature, strongly suggesting that the creation mechanism of the spins in electronic in nature, i.e., a charge transfer mechanism. However, our results suggest that the creation of the Si dangling bond in the Si-rich films are different. Last, we find that the creation of the N dangling-bond in N-rich films can be fit to a stretched exponential time dependence, which is characteristic of dispersive charge transport

  5. The relationship of microstructure and temperature to fracture mechanics parameters in reaction bonded silicon nitride

    International Nuclear Information System (INIS)

    Jennings, H.M.; Dalgleish, B.J.; Pratt, P.L.

    1978-01-01

    The development of physical properties in reaction bonded silicon nitride has been investigated over a range of temperatures and correlated with microstructure. Fracture mechanics parameters, elastic moduli, strength and critical defect size have been determined. The nitrided microstructure is shown to be directly related to these observed properties and these basic relationships can be used to produce material with improved properties. (orig.) [de

  6. On the photon annealing of silicon-implanted gallium-nitride layers

    International Nuclear Information System (INIS)

    Seleznev, B. I.; Moskalev, G. Ya.; Fedorov, D. G.

    2016-01-01

    The conditions for the formation of ion-doped layers in gallium nitride upon the incorporation of silicon ions followed by photon annealing in the presence of silicon dioxide and nitride coatings are analyzed. The conditions of the formation of ion-doped layers with a high degree of impurity activation are established. The temperature dependences of the surface concentration and mobility of charge carriers in ion-doped GaN layers annealed at different temperatures are studied.

  7. High temperature mechanical performance of a hot isostatically pressed silicon nitride

    Energy Technology Data Exchange (ETDEWEB)

    Wereszczak, A.A.; Ferber, M.K.; Jenkins, M.G.; Lin, C.K.J. [and others

    1996-01-01

    Silicon nitride ceramics are an attractive material of choice for designers and manufacturers of advanced gas turbine engine components for many reasons. These materials typically have potentially high temperatures of usefulness (up to 1400{degrees}C), are chemically inert, have a relatively low specific gravity (important for inertial effects), and are good thermal conductors (i.e., resistant to thermal shock). In order for manufacturers to take advantage of these inherent properties of silicon nitride, the high-temperature mechanical performance of the material must first be characterized. The mechanical response of silicon nitride to static, dynamic, and cyclic conditions at elevated temperatures, along with reliable and representative data, is critical information that gas turbine engine designers and manufacturers require for the confident insertion of silicon nitride components into gas turbine engines. This final report describes the high-temperature mechanical characterization and analyses that were conducted on a candidate structural silicon nitride ceramic. The high-temperature strength, static fatigue (creep rupture), and dynamic and cyclic fatigue performance were characterized. The efforts put forth were part of Work Breakdown Structure Subelement 3.2.1, {open_quotes}Rotor Data Base Generation.{close_quotes} PY6 is comparable to other hot isostatically pressed (HIPed) silicon nitrides currently being considered for advanced gas turbine engine applications.

  8. Studies on silicon nitrides; Chikka keiso ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-10-31

    Sinters of silicon nitrides have excellent properties as a structural material, but their technological repercussion effect is not as much as has been expected. The cause is in insufficient understanding on the mutual relationship between microstructures and mechanical properties. Therefore, methods of controlling structures were first discussed in the studies on synthesis of high-tenacity ceramics. In order to achieve high reliability in material strength, discussions were given on means to have a structure developed with high reproducibility. Development was performed on {beta} powder which shows no abnormal grain growth and is stable at elevated temperatures. Then, quantitative evaluation was made on factors to manifest a self-compounding structure with columnar particles grown in ultrafine particles. The relationship between its chemical composition, microstructure and mechanical properties was also discussed. Particle shapes of silicon carbides and their fracture tenacity values were considered theoretically by using a drawing model. To evaluate the microstructure, it is important to determine the grain boundary composition, whereas an electric field radiation type high-performance electron microscope was developed. In discussing the fracture mechanism, a model was structured for behavior of covalent binding crystals against external stress. 164 refs., 95 figs., 10 tabs.

  9. Molecular Surveillance of Viral Processes Using Silicon Nitride Membranes

    Directory of Open Access Journals (Sweden)

    Deborah F. Kelly

    2013-03-01

    Full Text Available Here we present new applications for silicon nitride (SiN membranes to evaluate biological processes. We determined that 50-nanometer thin films of SiN produced from silicon wafers were sufficiently durable to bind active rotavirus assemblies. A direct comparison of SiN microchips with conventional carbon support films indicated that SiN performs equivalent to the traditional substrate to prepare samples for Electron Microscopy (EM imaging. Likewise, SiN films coated with Ni-NTA affinity layers concentrated rotavirus particles similarly to affinity-coated carbon films. However, affinity-coated SiN membranes outperformed glow-discharged conventional carbon films 5-fold as indicated by the number of viral particles quantified in EM images. In addition, we were able to recapitulate viral uncoating and transcription mechanisms directed onto the microchip surfaces. EM images of these processes revealed the production of RNA transcripts emerging from active rotavirus complexes. These results were confirmed by the functional incorporation of radiolabeled nucleotides into the nascent RNA transcripts. Collectively, we demonstrate new uses for SiN membranes to perform molecular surveillance on life processes in real-time.

  10. Annealing and deposition effects of the chemical composition of silicon rich nitride

    DEFF Research Database (Denmark)

    Andersen, Karin Nordström; Svendsen, Winnie Edith; Stimpel-Lindner, T.

    2005-01-01

    Silicon-rich nitride, deposited by LPCVD, is a low stress amorphous material with a high refractive index. After deposition the silicon-rich nitride thin film is annealed at temperatures above 1100 oC to break N-H bonds, which have absorption peaks in the wavelength band important for optical...... in optical waveguides. This means that the annealing temperature must be high enough to break the N-H bonds, but no so high as to produce clusters. Therefore, the process window for an annealing step lies between 1100 and 1150 oC. The chemical composition of amorphous silicon-rich nitride has been...... investigated by Rutherford back scattering (RBS) and X-ray photoelectron spectroscopy (XPS). The influence of deposition parameters and annealing temperatures on the stoichiometry and the chemical bonds will be discussed. The origin of the clusters has been found to be silicon due to severe silicon out...

  11. Stable Protein-Repellent Zwitterionic Polymer Brushes Grafted from Silicon Nitride

    NARCIS (Netherlands)

    Nguyen, A.T.; Baggerman, J.; Paulusse, J.M.J.; Rijn, van C.J.M.; Zuilhof, H.

    2011-01-01

    Zwitterionic poly(sulfobetaine acrylamide) (SBMAA) brushes were grafted from silicon-rich silicon nitride (SixN4, x > 3) surfaces by atom transfer radical polymerization (ATRP) and studied in protein adsorption experiments. To this aim ATRP initiators were immobilized onto SixN4 through stable

  12. Stable Protein-Repellent Zwitterionic Polymer Brushes Grafted from Silicon Nitride

    NARCIS (Netherlands)

    Nguyen, Ai T.; Baggerman, Jacob; Paulusse, Jos Marie Johannes; van Rijn, Cees J.M.; Zuilhof, Han

    2011-01-01

    Zwitterionic poly(sulfobetaine acrylamide) (SBMAA) brushes were grafted from silicon-rich silicon nitride (SixN4, x > 3) surfaces by atom transfer radical polymerization (ATRP) and studied in protein adsorption experiments. To this aim ATRP initiators were immobilized onto SixN4 through stable Si−C

  13. Reaction sintering of a clay-containing silicon nitride bonded silicon carbide refractory

    International Nuclear Information System (INIS)

    Swenser, S.P.; Cheng, Y.B.

    1998-01-01

    Aspects of the reaction sequence for the reaction bonding of a cast refractory, which in the green state was composed of 79 wt-% SiC grit, 16 wt-% Si powder and 5 wt-% clay were established. As it was fired up to 1600 deg C in flowing N 2 (g), weight gains were noted and phase evolution was monitored by X-ray diffraction. However, details of the reaction sequence were not determined directly from this material because several reaction-bonding processes occurred simultaneously. Reaction features were ascertained by contrasting the weight changes and phase evolution in the refractory with those observed during reaction-bonding of (a) Si and clay without the SiC and (b) SiC and clay without the Si. In addition to silicon nitridation and the development of sialon phases by silicothermal and carbothermal reduction-nitridation processes, indirect evidence suggested that α-Si 3 N 4 formed by the carbothermal reduction-nitridation (CRN) of SiO(g). Copyright (1998) Australasian Ceramic Society

  14. Quantitative Auger depth profiling of LPCVD and PECVD silicon nitride films

    International Nuclear Information System (INIS)

    Keim, E.G.; Aite, K.

    1989-01-01

    Thin silicon nitride films (100-210 nm) with refractive indices varying from 1.90 to 2.10 were deposited on silicon substrates by low pressure chemical vapour deposition (LPCVD) and plasma enhanced chemical vapour deposition (PECVD). Rutherford backscattering spectrometry (RBS), ellipsometry, surface profiling measurements and Auger electron spectroscopy (AES) in combination with Ar + sputtering were used to characterize these films. We have found that the use of (p-p)heights of the Si LVV and N KLL Auger transitions in the first derivative of the energy distribution (dN(E)/dE) leads to an accurate determination of the silicon nitride composition in Auger depth profiles over a wide range of atomic Si/N ratios. Moreover, we have shown that the Si KLL Auger transition, generally considered to be a better probe than the low energy Si LVV Auger transition in determining the chemical composition of silicon nitride layers, leads to deviating results. (orig.)

  15. Microstructural and reliability in grinding of silicon nitride

    International Nuclear Information System (INIS)

    Liu, C.-C.

    2004-01-01

    A sintered Si 3 N 4 matrix has been characterized by TEM. The film thickness distribution of Si 3 N 4 was measured by high resolution transmission electron microscopy (HREM). Surface grinding is performed on two table speeds of 0.08 and 0.25 m s -1 with different depth of cut. The ground surfaces were observed with scanning electron microscopy (SEM). The surface texture was found to have greater dependence on depth of cut and table speed. The surface roughness is improved after smaller depth of cut. The flexural strength of ground specimens were measured by four-point flexure tests. The effect of depth of cut during grinding on the flexural strength and reliability of silicon nitride is investigated. The large depth of cut of 30 μm/pass resulted in a further decreased in strength of 540 MPa and a Weibull modulus of 7.5. When the depth of cut of 5 μm/pass were subjected to the ground specimens, the average strength was increased to 670 MPa and Weibull modulus to 9.1

  16. Fabrication and properties of graphene reinforced silicon nitride composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yaping; Li, Bin, E-mail: libin@nudt.edu.cn; Zhang, Changrui; Wang, Siqing; Liu, Kun; Yang, Bei

    2015-09-17

    Silicon nitride (Si{sub 3}N{sub 4}) ceramic composites reinforced with graphene platelets (GPLs) were prepared by hot pressed sintering and pressureless sintering respectively. Adequate intermixing of the GPLs and the ceramic powders was achieved in nmethyl-pyrrolidone (NMP) under ultrasonic vibration followed by ball-milling. The microstructure and phases of the Si{sub 3}N{sub 4} ceramic composites were investigated by Field Emission Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD). The effects of GPLs on the composites' mechanical properties were analyzed. The results showed that GPLs were well dispersed in the Si{sub 3}N{sub 4} ceramic matrix. β-Si{sub 3}N{sub 4,} O′-sialon and GPLs were present in the hot-pressed composites while pressureless sintered composites contain β-Si{sub 3}N{sub 4}, Si, SiC and GPLs. Graphene has the potential to improve the mechanical properties of both the hot pressed and pressureless sintered composites. Toughening effect of GPLs on the pressureless sintered composites appeared more effective than that on the hot pressed composites. Toughening mechanisms, such as pull-out, crack bridging and crack deflection induced by GPLs were observed in the composites prepared by the two methods.

  17. Bioactive silicon nitride: A new therapeutic material for osteoarthropathy

    Science.gov (United States)

    Pezzotti, Giuseppe; Marin, Elia; Adachi, Tetsuya; Rondinella, Alfredo; Boschetto, Francesco; Zhu, Wenliang; Sugano, Nobuhiko; Bock, Ryan M.; McEntire, Bryan; Bal, Sonny B.

    2017-03-01

    While the reciprocity between bioceramics and living cells is complex, it is principally governed by the implant’s surface chemistry. Consequently, a deeper understanding of the chemical interactions of bioceramics with living tissue could ultimately lead to new therapeutic strategies. However, the physical and chemical principles that govern these interactions remain unclear. The intricacies of this biological synergy are explored within this paper by examining the peculiar surface chemistry of a relatively new bioceramic, silicon nitride (Si3N4). Building upon prior research, this paper aims at obtaining new insights into the biological interactions between Si3N4 and living cells, as a consequence of the off-stoichiometric chemical nature of its surface at the nanometer scale. We show here yet unveiled details of surface chemistry and, based on these new data, formulate a model on how, ultimately, Si3N4 influences cellular signal transduction functions and differentiation mechanisms. In other words, we interpret its reciprocity with living cells in chemical terms. These new findings suggest that Si3N4 might provide unique new medicinal therapies and effective remedies for various bone or joint maladies and diseases.

  18. Fabrication and properties of graphene reinforced silicon nitride composite materials

    International Nuclear Information System (INIS)

    Yang, Yaping; Li, Bin; Zhang, Changrui; Wang, Siqing; Liu, Kun; Yang, Bei

    2015-01-01

    Silicon nitride (Si 3 N 4 ) ceramic composites reinforced with graphene platelets (GPLs) were prepared by hot pressed sintering and pressureless sintering respectively. Adequate intermixing of the GPLs and the ceramic powders was achieved in nmethyl-pyrrolidone (NMP) under ultrasonic vibration followed by ball-milling. The microstructure and phases of the Si 3 N 4 ceramic composites were investigated by Field Emission Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD). The effects of GPLs on the composites' mechanical properties were analyzed. The results showed that GPLs were well dispersed in the Si 3 N 4 ceramic matrix. β-Si 3 N 4, O′-sialon and GPLs were present in the hot-pressed composites while pressureless sintered composites contain β-Si 3 N 4 , Si, SiC and GPLs. Graphene has the potential to improve the mechanical properties of both the hot pressed and pressureless sintered composites. Toughening effect of GPLs on the pressureless sintered composites appeared more effective than that on the hot pressed composites. Toughening mechanisms, such as pull-out, crack bridging and crack deflection induced by GPLs were observed in the composites prepared by the two methods

  19. Ag doped silicon nitride nanocomposites for embedded plasmonics

    Energy Technology Data Exchange (ETDEWEB)

    Bayle, M.; Bonafos, C., E-mail: bonafos@cemes.fr; Benzo, P.; Benassayag, G.; Pécassou, B.; Carles, R. [CEMES-CNRS and Université de Toulouse, 29 rue J. Marvig, 31055 Toulouse, Cedex 04 (France); Khomenkova, L.; Gourbilleau, F. [CIMAP, CNRS/CEA/ENSICAEN/UCBN, 6 Boulevard Maréchal Juin, 14050 Caen, Cedex 4 (France)

    2015-09-07

    The localized surface plasmon-polariton resonance (LSPR) of noble metal nanoparticles (NPs) is widely exploited for enhanced optical spectroscopies of molecules, nonlinear optics, photothermal therapy, photovoltaics, or more recently in plasmoelectronics and photocatalysis. The LSPR frequency depends not only of the noble metal NP material, shape, and size but also of its environment, i.e., of the embedding matrix. In this paper, Ag-NPs have been fabricated by low energy ion beam synthesis in silicon nitride (SiN{sub x}) matrices. By coupling the high refractive index of SiN{sub x} to the relevant choice of dielectric thickness in a SiN{sub x}/Si bilayer for an optimum antireflective effect, a very sharp plasmonic optical interference is obtained in mid-range of the visible spectrum (2.6 eV). The diffusion barrier property of the host SiN{sub x} matrix allows for the introduction of a high amount of Ag and the formation of a high density of Ag-NPs that nucleate during the implantation process. Under specific implantation conditions, in-plane self-organization effects are obtained in this matrix that could be the result of a metastable coarsening regime.

  20. Silicon Nitride Background in Nanophotonic Waveguide Enhanced Raman Spectroscopy

    Directory of Open Access Journals (Sweden)

    Ashim Dhakal

    2017-02-01

    Full Text Available Recent studies have shown that evanescent Raman spectroscopy using a silicon nitride (SiN nanophotonic waveguide platform has higher signal enhancement when compared to free-space systems. However, signal-to-noise ratio from the waveguide at a low analyte concentration is constrained by the shot-noise from the background light originating from the waveguide itself. Hence, understanding the origin and properties of this waveguide background luminescence (WGBL is essential to developing mitigation strategies. Here, we identify the dominating component of the WGBL spectrum composed of a broad Raman scattering due to momentum selection-rule breaking in amorphous materials, and several peaks specific to molecules embedded in the core. We determine the maximum of the Raman scattering efficiency of the WGBL at room temperature for 785 nm excitation to be 4.5 ± 1 × 10−9 cm−1·sr−1, at a Stokes shift of 200 cm−1. This efficiency decreases monotonically for higher Stokes shifts. Additionally, we also demonstrate the use of slotted waveguides and quasi-transverse magnetic polarization as some mitigation strategies.

  1. Elasticity and inelasticity of silicon nitride/boron nitride fibrous monoliths.

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, B. I.; Burenkov, Yu. A.; Kardashev, B. K.; Singh, D.; Goretta, K. C.; de Arellano-Lopez, A. R.; Energy Technology; Russian Academy of Sciences; Univer. de Sevilla

    2001-01-01

    A study is reported on the effect of temperature and elastic vibration amplitude on Young's modulus E and internal friction in Si{sub 3}N{sub 4} and BN ceramic samples and Si{sub 3}N{sub 4}/BN monoliths obtained by hot pressing of BN-coated Si{sub 3}N{sub 4} fibers. The fibers were arranged along, across, or both along and across the specimen axis. The E measurements were carried out under thermal cycling within the 20-600 C range. It was found that high-modulus silicon-nitride specimens possess a high thermal stability; the E(T) dependences obtained under heating and cooling coincide well with one another. The low-modulus BN ceramic exhibits a considerable hysteresis, thus indicating evolution of the defect structure under the action of thermoelastic (internal) stresses. Monoliths demonstrate a qualitatively similar behavior (with hysteresis). This behavior of the elastic modulus is possible under microplastic deformation initiated by internal stresses. The presence of microplastic shear in all the materials studied is supported by the character of the amplitude dependences of internal friction and the Young's modulus. The experimental data obtained are discussed in terms of a model in which the temperature dependences of the elastic modulus and their features are accounted for by both microplastic deformation and nonlinear lattice-atom vibrations, which depend on internal stresses.

  2. Annealing temperature dependence of photoluminescent characteristics of silicon nanocrystals embedded in silicon-rich silicon nitride films grown by PECVD

    International Nuclear Information System (INIS)

    Chao, D.S.; Liang, J.H.

    2013-01-01

    Recently, light emission from silicon nanostructures has gained great interest due to its promising potential of realizing silicon-based optoelectronic applications. In this study, luminescent silicon nanocrystals (Si–NCs) were in situ synthesized in silicon-rich silicon nitride (SRSN) films grown by plasma-enhanced chemical vapor deposition (PECVD). SRSN films with various excess silicon contents were deposited by adjusting SiH 4 flow rate to 100 and 200 sccm and keeping NH 3 one at 40 sccm, and followed by furnace annealing (FA) treatments at 600, 850 and 1100 °C for 1 h. The effects of excess silicon content and post-annealing temperature on optical properties of Si–NCs were investigated by photoluminescence (PL) and Fourier transform infrared spectroscopy (FTIR). The origins of two groups of PL peaks found in this study can be attributed to defect-related interface states and quantum confinement effects (QCE). Defect-related interface states lead to the photon energy levels almost kept constant at about 3.4 eV, while QCE results in visible and tunable PL emission in the spectral range of yellow and blue light which depends on excess silicon content and post-annealing temperature. In addition, PL intensity was also demonstrated to be highly correlative to the excess silicon content and post-annealing temperature due to its corresponding effects on size, density, crystallinity, and surface passivation of Si–NCs. Considering the trade-off between surface passivation and structural properties of Si–NCs, an optimal post-annealing temperature of 600 °C was suggested to maximize the PL intensity of the SRSN films

  3. Process for producing silicon nitride based articles of high fracture toughness and strength

    Science.gov (United States)

    Huckabee, M.; Buljan, S.T.; Neil, J.T.

    1991-09-10

    A process for producing a silicon nitride-based article of improved fracture toughness and strength is disclosed. The process involves densifying to at least 98% of theoretical density a mixture including (a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon nitride powder of an average particle size of about 0.2 [mu]m and a surface area of about 8-12 m[sup 2]/g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 [mu]m and a surface area of about 2-4 m[sup 2]/g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified article an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. Optionally, the mixture may be blended with a binder and injection molded to form a green body, which then may be densified by, for example, hot isostatic pressing.

  4. Application of plasma silicon nitride to crystalline thin-film silicon solar cells. Paper

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, J.; Oberbeck, L.; Rinke, T.J.; Berge, C.; Bergmann, R.B.

    2002-07-01

    We use plasma-enhanced chemical vapour deposition to deposit silicon nitride (SiN{sub x}) films at low temperature(400 C) onto the front surface of two different types of crystalline thin-film Si solar cells. The silicon nitride acts as an excellent antireflection coating on Si and provides a very high degree of electronic surface passivation over a wide range of compositions, including near-stoichiometric and Si-rich SiN{sub x}. Application of stoichiometric SiN{sub x} to non-textured thin-film cells, epitaxially grown at low temperature by ion-assisted deposition onto a monocrystalline Si substrate, results in an open-circuit voltage of 622 mV, a short-circuit current density of 26.6 mA/cm{sup 2} and an efficiency of 12.7%. It is shown that the SiN{sub x}-passivated in-situ grown n{sup +}-emitter of this cell type allows to reach open-circuit voltages of up to 667 mV. Silicon-rich SiN{sub x} is applied to the phosphorus-diffused n{sup +}-emitter of a textured thin-film cell on a glass superstrate fabricated by layer-transfer. The emitter saturation current density of these cells is only 40-64 fA/cm{sup 2}, which allows for open-circuit voltages of up to 699 mV. An impressively high open-circuit voltage of 638 mV and a short-circuit current density of 32.0 mA/cm{sup 2} are obtained for a 25 {mu}m thick SiN{sub x}-passivated, random pyramid-textured transfer cell. A transfer cell efficiency of 15.3% is independently confirmed.

  5. Enhanced Electroluminescence from Silicon Quantum Dots Embedded in Silicon Nitride Thin Films Coupled with Gold Nanoparticles in Light Emitting Devices

    Directory of Open Access Journals (Sweden)

    Ana Luz Muñoz-Rosas

    2018-03-01

    Full Text Available Nowadays, the use of plasmonic metal layers to improve the photonic emission characteristics of several semiconductor quantum dots is a booming tool. In this work, we report the use of silicon quantum dots (SiQDs embedded in a silicon nitride thin film coupled with an ultra-thin gold film (AuNPs to fabricate light emitting devices. We used the remote plasma enhanced chemical vapor deposition technique (RPECVD in order to grow two types of silicon nitride thin films. One with an almost stoichiometric composition, acting as non-radiative spacer; the other one, with a silicon excess in its chemical composition, which causes the formation of silicon quantum dots imbibed in the silicon nitride thin film. The ultra-thin gold film was deposited by the direct current (DC-sputtering technique, and an aluminum doped zinc oxide thin film (AZO which was deposited by means of ultrasonic spray pyrolysis, plays the role of the ohmic metal-like electrode. We found that there is a maximum electroluminescence (EL enhancement when the appropriate AuNPs-spacer-SiQDs configuration is used. This EL is achieved at a moderate turn-on voltage of 11 V, and the EL enhancement is around four times bigger than the photoluminescence (PL enhancement of the same AuNPs-spacer-SiQDs configuration. From our experimental results, we surmise that EL enhancement may indeed be due to a plasmonic coupling. This kind of silicon-based LEDs has the potential for technology transfer.

  6. Elastocapillary folding of three dimensional micro-structures using water pumped through the wafer via a silicon nitride tube

    NARCIS (Netherlands)

    Legrain, A.B.H.; Berenschot, Johan W.; Sanders, Remco G.P.; Ma, Kechun; Tas, Niels Roelof; Abelmann, Leon

    2011-01-01

    In this paper we present the first investigation of a batch method for folding of threedimensional micrometer-sized silicon nitride structures by capillary forces. Silicon nitride tubes have been designed and fabricated using DRIE at the center of the planar origami patterns of the structures. Water

  7. Ab initio design of nanostructures for solar energy conversion: a case study on silicon nitride nanowire.

    Science.gov (United States)

    Pan, Hui

    2014-01-01

    Design of novel materials for efficient solar energy conversion is critical to the development of green energy technology. In this work, we present a first-principles study on the design of nanostructures for solar energy harvesting on the basis of the density functional theory. We show that the indirect band structure of bulk silicon nitride is transferred to direct bandgap in nanowire. We find that intermediate bands can be created by doping, leading to enhancement of sunlight absorption. We further show that codoping not only reduces the bandgap and introduces intermediate bands but also enhances the solubility of dopants in silicon nitride nanowires due to reduced formation energy of substitution. Importantly, the codoped nanowire is ferromagnetic, leading to the improvement of carrier mobility. The silicon nitride nanowires with direct bandgap, intermediate bands, and ferromagnetism may be applicable to solar energy harvesting.

  8. Transient and steady-state erosion of in-situ reinforced silicon nitride

    Energy Technology Data Exchange (ETDEWEB)

    Karasek, K.R. [Allied Signal Research and Technology, Des Plaines, IL (United States); Whalen, P.J. [Allied Signal, Inc., Morristown, NJ (United States); Rateick, R.G. Jr. [Allied Signal Aerospace, South Bend, IN (United States); Hamilton, A.C. [Michigan Technological Univ., Houghton, MI (United States); Routbort, J.L. [Argonne National Lab., IL (United States)

    1994-10-01

    Relative to most other materials silicon nitride is very erosion resistant. However, the resulting surface flaws degrade strength - a serious concern for component designers. AlliedSignal Ceramic Components GS-44 in-situ reinforced silicon nitride was eroded in a slinger apparatus. Both transient (extremely low level) and steady-state erosion regimes were investigated. Alumina particles with effective average diameters of 140 Jim and 63 {mu}m were used at velocities of 50 m/s, 100 m/s, and 138 m/s. Biaxial tensile strength was measured. Strength decreased by about 15% after a very small erodent dosage and then remained virtually constant with further erosion. In-situ reinforcement produces R-curve behavior in which the fracture toughness increases with crack size. The effect of this is quite dramatic with strength loss being significantly less than expected for a normal silicon nitride with constant fracture toughness.

  9. Preparation and mechanical properties of carbon nanotube-silicon nitride nano-ceramic matrix composites

    Science.gov (United States)

    Tian, C. Y.; Jiang, H.

    2018-01-01

    Carbon nanotube-silicon nitride nano-ceramic matrix composites were fabricated by hot-pressing nano-sized Si3N4 powders and carbon nanotubes. The effect of CNTs on the mechanical properties of silicon nitride was researched. The phase compositions and the microstructure characteristics of the samples as well as the distribution of carbon nanotube in the silicon nitride ceramic were analyzed by X-ray diffraction and scanning electron microscope. The results show that the microstructure of composites consists mainly of α-Si3N4, β-Si3N4, Si2N2O and carbon natubes. The addition of proper amount of carbon nanotubes can improve the fracture toughness and the flexural strength, and the optimal amount of carbon nanotube are both 3wt.%. However the Vickers hardness values decrease with the increase of carbon nanotubes content.

  10. Effect of post-deposition implantation and annealing on the properties of PECVD deposited silicon nitride films

    International Nuclear Information System (INIS)

    Shams, Q.A.

    1988-01-01

    Recently it has been shown that memory-quality silicon nitride can be deposited using plasma enhanced chemical vapor deposition (PECVD). Nitrogen implantation and post-deposition annealing resulted in improved memory properties of MNOS devices. The primary objective of the work described here is the continuation of the above work. Silicon nitride films were deposited using argon as the carrier gas and evaluated in terms of memory performance as the charge-trapping layer in the metal-nitride-oxide-silicon (MNOS) capacitor structure. The bonding structure of PECVD silicon nitride was modified by annealing in different ambients at temperatures higher than the deposition temperature. Post-deposition ion implantation was used to introduce argon into the films in an attempt to influence the transfer, trapping, and emission of charge during write/erase exercising of the MNOS devices. Results show that the memory performance of PECVD silicon nitride is sensitive to the deposition parameters and post-deposition processing

  11. Low-stress silicon nitride layers for MEMS applications

    Science.gov (United States)

    Iliescu, Ciprian; Wei, Jiashen; Chen, Bangtao; Ong, Poh Lam; Tay, Francis E. H.

    2006-12-01

    The paper presents two deposition methods for generation of SiN x layers with "zero" residual stress in PECVD reactors: mixed frequency and high power in high frequency mode (13.56 MHz). Traditionally, mix frequency mode is commonly used to produce low stress SiN x layers, which alternatively applies the HF and LF mode. However, due to the low deposition rate of LF mode, the combined deposition rate of mix frequency is quite small in order to produce homogenous SiN x layers. In the second method, a high power which was up to 600 W has been used, may also produce low residual stress (0-20 MPa), with higher deposition rate (250 to 350 nm/min). The higher power not only leads to higher dissociation rates of gases which results in higher deposition rates, but also brings higher N bonding in the SiN x films and higher compressive stress from higher volume expansion of SiN x films, which compensates the tensile stress and produces low residual stress. In addition, the paper investigates the influence of other important parameters which have great impact to the residual stress and deposition rates, such as reactant gases flow rate and pressure. By using the final optimized recipe, masking layer for anisotropic wet etching in KOH and silicon nitride cantilever have been successfully fabricated based on the low stress SiN x layers. Moreover, nanoporous membrane with 400nm pores has also been fabricated and tested for cell culture. By cultivating the mouse D1 mesenchymal stem cells on top of the nanoporous membrane, the results showed that mouse D1 mesenchymal stem cells were able to grow well. This shows that the nanoporous membrane can be used as the platform for interfacing with living cells to become biocapsules for biomolecular separation.

  12. Silicon nitride back-end optics for biosensor applications

    Science.gov (United States)

    Romero-García, Sebastian; Merget, Florian; Zhong, Frank C.; Finkelstein, Hod; Witzens, Jeremy

    2013-05-01

    Silicon nitride (SiN) is a promising candidate material for becoming a standard high-performance solution for integrated biophotonics applications in the visible spectrum. As a key feature, its compatibility with the complementary-oxidemetal- semiconductor (CMOS) technology permits cost reduction at large manufacturing volumes that is particularly advantageous for manufacturing consumables. In this work, we show that the back-end deposition of a thin SiN film enables the large light-cladding interaction desirable for biosensing applications while the refractive index contrast of the technology (Δn ≍ 0.5) also enables a considerable level of integration with reduced waveguide bend radii. Design and experimental validation also show that several advantages are derived from the moderate SiN/SiO2 refractive index contrast, such as lower scattering losses in interconnection waveguides and relaxed tolerances to fabrication imperfections as compared to higher refractive index contrast material systems. As a drawback, a moderate refractive index contrast also makes the implementation of compact grating couplers more challenging, due to the fact that only a relatively weak scattering strength can be achieved. Thereby, the beam diffracted by the grating tends to be rather large and consequently exhibit stringent angular alignment tolerances. Here, we experimentally demonstrate how a proper design of the bottom and top cladding oxide thicknesses allows reduction of the full-width at half maximum (FWHM) and alleviates this problem. Additionally, the inclusion of a CMOS-compatible AlCu/TiN bottom reflector further decreases the FWHM and increases the coupling efficiency. Finally, we show that focusing grating designs greatly reduce the device footprint without penalizing the device metrics.

  13. Thermogravimetric analysis of silicon carbide-silicon nitride polycarbosilazane precursor during pyrolysis from ambient to 1000 C

    Science.gov (United States)

    Ledbetter, F. E., III; Daniels, J. G.; Clemons, J. M.; Hundley, N. H.; Penn, B. G.

    1984-01-01

    Thermogravimetric analysis data are presented on the unmeltable polycarbosilazane precursor of silicon carbide-silicon nitride fibers, over the room temperature-1000 C range in a nitrogen atmosphere, in order to establish the weight loss at various temperatures during the precursor's pyrolysis to the fiber material. The fibers obtained by this method are excellent candidates for use in applications where the oxidation of carbon fibers (above 400 C) renders them unsuitable.

  14. Alternative Liquid Fuel Effects on Cooled Silicon Nitride Marine Gas Turbine Airfoils

    Energy Technology Data Exchange (ETDEWEB)

    Holowczak, J.

    2002-03-01

    With prior support from the Office of Naval Research, DARPA, and U.S. Department of Energy, United Technologies is developing and engine environment testing what we believe to be the first internally cooled silicon nitride ceramic turbine vane in the United States. The vanes are being developed for the FT8, an aeroderivative stationary/marine gas turbine. The current effort resulted in further manufacturing and development and prototyping by two U.S. based gas turbine grade silicon nitride component manufacturers, preliminary development of both alumina, and YTRIA based environmental barrier coatings (EBC's) and testing or ceramic vanes with an EBC coating.

  15. Microstructure and initial growth characteristics of the low temperature microcrystalline silicon films on silicon nitride surface

    International Nuclear Information System (INIS)

    Park, Young-Bae; Rhee, Shi-Woo

    2001-01-01

    Microstructure and initial growth characteristics of the hydrogenated microcrystalline Si (μc-Si:H) films grown on hydrogenated amorphous silicon nitride (a-SiN x :H) surface at low temperature were investigated using high resolution transmission electron microscope and micro-Raman spectroscopy. With increasing the Si and Si - H contents in the SiN x :H surfaces, μc-Si crystallites, a few nanometers in size, were directly grown on amorphous nitride surfaces. It is believed that the crystallites were grown through the nucleation and phase transition from amorphous to crystal in a hydrogen-rich ambient of gas phase and growing surface. The crystallite growth characteristics on the dielectric surface were dependent on the stoichiometric (x=N/Si) ratio corresponding hydrogen bond configuration of the SiN x :H surface. Surface facetting and anisotropic growth of the Si crystallites resulted from the different growth rate on the different lattice planes of Si. No twins and stacking faults were observed in the (111) lattice planes of the Si crystallites surrounding the a-Si matrix. This atomic-scale structure was considered to be the characteristic of the low temperature crystallization of the μc-Si:H by the strain relaxation of crystallites in the a-Si:H matrix. [copyright] 2001 American Institute of Physics

  16. Process for the production of metal nitride sintered bodies and resultant silicon nitride and aluminum nitride sintered bodies

    Science.gov (United States)

    Yajima, S.; Omori, M.; Hayashi, J.; Kayano, H.; Hamano, M.

    1983-01-01

    A process for the manufacture of metal nitride sintered bodies, in particular, a process in which a mixture of metal nitrite powders is shaped and heated together with a binding agent is described. Of the metal nitrides Si3N4 and AIN were used especially frequently because of their excellent properties at high temperatures. The goal is to produce a process for metal nitride sintered bodies with high strength, high corrosion resistance, thermal shock resistance, thermal shock resistance, and avoidance of previously known faults.

  17. Argon plasma treatment of silicon nitride (SiN) for improved antireflection coating on c-Si solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Hemanta; Mitra, Suchismita; Saha, Hiranmay; Datta, Swapan Kumar; Banerjee, Chandan, E-mail: chandanbanerjee74@gmail.com

    2017-01-15

    Highlights: • Antireflection properties of argon plasma treated silicon nitride layer and its effect on crystalline silicon solar cell. • The reduction in reflection due to the formation of a silicon oxynitride/silicon nitride double layer. • EQE reveals a relative increase of 2.72% in J{sub sc} and 4.46% in conversion efficiency. - Abstract: Antireflection properties of argon plasma treated silicon nitride layer and its effect on crystalline silicon solar cell is presented here. Hydrogenated silicon nitride (a-SiN:H) layer has been deposited on a silicon substrate by Plasma Enhanced Chemical Vapour Deposition (PECVD) using a mixture of silane (SiH{sub 4}), ammonia (NH{sub 3}) and hydrogen (H{sub 2}) gases followed by a argon plasma treatment. Optical analysis reveals a significant reduction in reflectance after argon plasma treatment of silicon nitride layer. While FESEM shows nanostructures on the surface of the silicon nitride film, FTIR reveals a change in Si−N, Si−O and N−H bonds. On the other hand, ellipsometry shows the variation of refractive index and formation of double layer. Finally, a c-Si solar cell has been fabricated with the said anti-reflection coating. External quantum efficiency reveals a relative increase of 2.72% in the short circuit current density and 4.46% in conversion efficiency over a baseline efficiency of 16.58%.

  18. Formation of nanocrystals embedded in a silicon nitride film at a low temperature ({<=}200 deg. C)

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyoung-Min; Kim, Tae-Hwan [Department of Nano Science and Technology, University of Seoul, Seoul 130-743 (Korea, Republic of); Hong, Wan-Shick [Department of Nano Science and Technology, University of Seoul, Seoul 130-743 (Korea, Republic of)], E-mail: wshong@uos.ac.kr

    2008-12-15

    Silicon-rich silicon nitride films with embedded silicon nanocrystals (Si NCs) were fabricated successfully on plastic substrates at a low temperature by catalytic chemical vapor deposition. A mixture of SiH{sub 4}, NH{sub 3} and H{sub 2} was used as a source gas. Formation of the silicon nanocrystals was analyzed by photoluminescence spectra and was confirmed by transmission electron microscopy. The formation of Si NCs required an H{sub 2}/SiH{sub 4} mixture ratio that was higher than four.

  19. Helium ion beam induced electron emission from insulating silicon nitride films under charging conditions

    Science.gov (United States)

    Petrov, Yu. V.; Anikeva, A. E.; Vyvenko, O. F.

    2018-06-01

    Secondary electron emission from thin silicon nitride films of different thicknesses on silicon excited by helium ions with energies from 15 to 35 keV was investigated in the helium ion microscope. Secondary electron yield measured with Everhart-Thornley detector decreased with the irradiation time because of the charging of insulating films tending to zero or reaching a non-zero value for relatively thick or thin films, respectively. The finiteness of secondary electron yield value, which was found to be proportional to electronic energy losses of the helium ion in silicon substrate, can be explained by the electron emission excited from the substrate by the helium ions. The method of measurement of secondary electron energy distribution from insulators was suggested, and secondary electron energy distribution from silicon nitride was obtained.

  20. Joining and interface characterization of in situ reinforced silicon nitride

    Energy Technology Data Exchange (ETDEWEB)

    Asthana, R., E-mail: asthanar@uwstout.edu [Department of Engineering and Technology, 326 FH, University of Wisconsin-Stout, Menomonie, WI 54751 (United States); Singh, M., E-mail: Mrityunjay.Singh@nasa.gov [Ohio Aerospace Institute, NASA Glenn Research Center, Cleveland, OH 44135 (United States); Martinez-Fernandez, J., E-mail: Martinez@us.es [Dpto. Física de la Materia Condensada-ICMSE, Universidad de Sevilla-CSIC, Avda. Reina Mercedes, s/n, 41012 Sevilla (Spain)

    2013-03-05

    Highlights: ► AS800 Si{sub 3}N{sub 4} brazed using oxidation-resistant, high use-temperature braze Cu-ABA. ► Interface enriched in Ti and Si but not in Y, La, and Sr (from Y{sub 2}O{sub 3}, La{sub 2}O{sub 3} and SrO). ► Rapid early-stage kinetic evident in constant layer thickness, composition with time. ► Highly textured large grains of Cu and features associated with plastic deformation. -- Abstract: Copper-base active metal interlayers were used to bond in situ reinforced silicon nitride (Honeywell AS800) at 1317 K for 5 and 30 min in vacuum. The joints were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), electron back scattered diffraction (EBSD), and transmission electron microscopy (TEM). A Ti-rich interaction zone (∼3.0–3.5 μm thick) formed at the Si{sub 3}N{sub 4}/braze interface. This reaction layer grew toward the inner part of the joint with a featureless microstructure, creating a strong bond. Regions of a Ti-rich phase were frequently found next to the reaction layer but surrounded by the Cu alloy. Extensive Ti and Si enrichments were noted at the interface but there was no evidence of interfacial segregation of Y, La, and Sr (from Y{sub 2}O{sub 3}, La{sub 2}O{sub 3} and SrO, added as sintering aids). The reaction layer thickness and composition did not change when brazing time increased from 5 min to 30 min suggesting rapid growth kinetics in the early stages of reaction. The joints were crack-free and showed features associated with plastic deformation, which indicated that the metal interlayer accommodated strain associated with CTE mismatch. The inner part of the joint consisted of highly textured large grains of the braze alloy.

  1. Life prediction and mechanical reliability of NT551 silicon nitride

    Science.gov (United States)

    Andrews, Mark Jay

    The inert strength and fatigue performance of a diesel engine exhaust valve made from silicon nitride (Si3N4) ceramic were assessed. The Si3N4 characterized in this study was manufactured by Saint Gobain/Norton Industrial Ceramics and was designated as NT551. The evaluation was made utilizing a probabilistic life prediction algorithm that combined censored test specimen strength data with a Weibull distribution function and the stress field of the ceramic valve obtained from finite element analysis. The major assumptions of the life prediction algorithm are that the bulk ceramic material is isotropic and homogeneous and that the strength-limiting flaws are uniformly distributed. The results from mechanical testing indicated that NT551 was not a homogeneous ceramic and that its strength were functions of temperature, loading rate, and machining orientation. Fractographic analysis identified four different failure modes; 2 were identified as inhomogeneities that were located throughout the bulk of NT551 and were due to processing operations. The fractographic analysis concluded that the strength degradation of NT551 observed from the temperature and loading rate test parameters was due to a change of state that occurred in its secondary phase. Pristine and engine-tested valves made from NT551 were loaded to failure and the inert strengths were obtained. Fractographic analysis of the valves identified the same four failure mechanisms as found with the test specimens. The fatigue performance and the inert strength of the Si3N 4 valves were assessed from censored and uncensored test specimen strength data, respectively. The inert strength failure probability predictions were compared to the inert strength of the Si3N4 valves. The inert strength failure probability predictions were more conservative than the strength of the valves. The lack of correlation between predicted and actual valve strength was due to the nonuniform distribution of inhomogeneities present in NT

  2. TOPICAL REVIEW Textured silicon nitride: processing and anisotropic properties

    Directory of Open Access Journals (Sweden)

    Xinwen Zhu and Yoshio Sakka

    2008-01-01

    Full Text Available Textured silicon nitride (Si3N4 has been intensively studied over the past 15 years because of its use for achieving its superthermal and mechanical properties. In this review we present the fundamental aspects of the processing and anisotropic properties of textured Si3N4, with emphasis on the anisotropic and abnormal grain growth of β-Si3N4, texture structure and texture analysis, processing methods and anisotropic properties. On the basis of the texturing mechanisms, the processing methods described in this article have been classified into two types: hot-working (HW and templated grain growth (TGG. The HW method includes the hot-pressing, hot-forging and sinter-forging techniques, and the TGG method includes the cold-pressing, extrusion, tape-casting and strong magnetic field alignment techniques for β-Si3N4 seed crystals. Each processing technique is thoroughly discussed in terms of theoretical models and experimental data, including the texturing mechanisms and the factors affecting texture development. Also, methods of synthesizing the rodlike β-Si3N4 single crystals are presented. Various anisotropic properties of textured Si3 N4 and their origins are thoroughly described and discussed, such as hardness, elastic modulus, bending strength, fracture toughness, fracture energy, creep behavior, tribological and wear behavior, erosion behavior, contact damage behavior and thermal conductivity. Models are analyzed to determine the thermal anisotropy by considering the intrinsic thermal anisotropy, degree of orientation and various microstructure factors. Textured porous Si3N4 with a unique microstructure composed of oriented elongated β-Si3N4 and anisotropic pores is also described for the first time, with emphasis on its unique mechanical and thermal-mechanical properties. Moreover, as an important related material, textured α-Sialon is also reviewed, because the presence of elongated α-Sialon grains allows the production of textured

  3. High Temperature Corrosion of Silicon Carbide and Silicon Nitride in Water Vapor

    Science.gov (United States)

    Opila, E. J.; Robinson, Raymond C.; Cuy, Michael D.; Gray, Hugh R. (Technical Monitor)

    2002-01-01

    Silicon carbide (SiC) and silicon nitride (Si3N4) are proposed for applications in high temperature combustion environments containing water vapor. Both SiC and Si3N4 react with water vapor to form a silica (SiO2) scale. It is therefore important to understand the durability of SiC, Si3N4 and SiO2 in water vapor. Thermogravimetric analyses, furnace exposures and burner rig results were obtained for these materials in water vapor at temperatures between 1100 and 1450 C and water vapor partial pressures ranging from 0.1 to 3.1 atm. First, the oxidation of SiC and Si3N4 in water vapor is considered. The parabolic kinetic rate law, rate dependence on water vapor partial pressure, and oxidation mechanism are discussed. Second, the volatilization of silica to form Si(OH)4(g) is examined. Mass spectrometric results, the linear kinetic rate law and a volatilization model based on diffusion through a gas boundary layer are discussed. Finally, the combined oxidation and volatilization reactions, which occur when SiC or Si3N4 are exposed in a water vapor-containing environment, are presented. Both experimental evidence and a model for the paralinear kinetic rate law are shown for these simultaneous oxidation and volatilization reactions.

  4. Nano-structure and tribological properties of B+ and Ti+ co-implanted silicon nitride

    International Nuclear Information System (INIS)

    Nakamura, Naoki; Noda, Katsutoshi; Yamauchi, Yukihiko

    2005-01-01

    Silicon nitride ceramics have been co-implanted with boron and titanium ions at a fluence of 2 x 10 17 ions/cm 2 and an energy of 200 keV. TEM results indicated that the boron and titanium-implanted layers were amorphized separately and titanium nitride nano-crystallites were formed in the titanium-implanted layer. XPS results indicated that the implantation profile varied a little depending on the ion implantation sequence of boron and titanium ions, with the boron implantation peak shifting to a shallower position when implanted after Ti + -implantation. Wear tests of these ion-implanted materials were carried out using a block-on-ring wear tester under non-lubricated conditions against commercially available silicon nitride materials. The specific wear rate was reduced by ion implantation and showed that the specific wear rate of Ti + -implanted sample was the lowest, followed by B + , Ti + co-implanted and B + -implanted samples

  5. Plasma-enhanced growth, composition, and refractive index of silicon oxy-nitride films

    DEFF Research Database (Denmark)

    Mattsson, Kent Erik

    1995-01-01

    Secondary ion mass spectrometry and refractive index measurements have been carried out on silicon oxy-nitride produced by plasma-enhanced chemical vapor deposition (PECVD). Nitrous oxide and ammonia were added to a constant flow of 2% silane in nitrogen, to produce oxy-nitride films with atomic...... nitrogen concentrations between 2 and 10 at. %. A simple atomic valence model is found to describe both the measured atomic concentrations and published material compositions for silicon oxy-nitride produced by PECVD. A relation between the Si–N bond concentration and the refractive index is found......-product. A model, that combine the chemical net reaction and the stoichiometric rules, is found to agree with measured deposition rates for given material compositions. Effects of annealing in a nitrogen atmosphere has been investigated for the 400 °C– 1100 °C temperature range. It is observed that PECVD oxy...

  6. Improved reaction sintered silicon nitride. [protective coatings to improve oxidation resistance

    Science.gov (United States)

    Baumgartner, H. R.

    1978-01-01

    Processing treatments were applied to as-nitrided reaction sintered silicon nitride (RSSN) with the purposes of improving strength after processing to above 350 MN/m2 and improving strength after oxidation exposure. The experimental approaches are divided into three broad classifications: sintering of surface-applied powders; impregnation of solution followed by further thermal processing; and infiltration of molten silicon and subsequent carburization or nitridation of the silicon. The impregnation of RSSN with solutions of aluminum nitrate and zirconyl chloride, followed by heating at 1400-1500 C in a nitrogen atmosphere containing silicon monoxide, improved RSSN strength and oxidation resistance. The room temperature bend strength of RSSN was increased nearly fifty percent above the untreated strength with mean absolute strengths up to 420 MN/m2. Strengths of treated samples that were measured after a 12 hour oxidation exposure in air were up to 90 percent of the original as-nitrided strength, as compared to retained strengths in the range of 35 to 60 percent for untreated RSSN after the same oxidation exposure.

  7. Size-dependent effective Young’s modulus of silicon nitride cantilevers

    NARCIS (Netherlands)

    Babaei Gavan, K.; Westra, H.J.R.; Van der Drift, E.W.J.M.; Venstra, W.J.; Van der Zant, H.S.J.

    2009-01-01

    The effective Young’s modulus of silicon nitride cantilevers is determined for thicknesses in the range of 20–684 nm by measuring resonance frequencies from thermal noise spectra. A significant deviation from the bulk value is observed for cantilevers thinner than 150 nm. To explain the observations

  8. On the intrinsic moisture permeation rate of remote microwave plasma-deposited silicon nitride layers

    NARCIS (Netherlands)

    van Assche, F. J. H.; Unnikrishnan, S.; Michels, J. J.; van Mol, A. M. B.; van de Weijer, P.; M. C. M. van de Sanden,; Creatore, M.

    2014-01-01

    We report on a low substrate temperature (110 °C) remote microwave plasma-enhanced chemical vapor deposition (PECVD) process of silicon nitride barrier layers against moisture permeation for organic light emitting diodes (OLEDs) and other moisture sensitive devices such as organic

  9. Bio-functionalization of silicon nitride-based piezo-resistive ...

    Indian Academy of Sciences (India)

    Methods of bio-functionalize silicon nitride involve process steps to ... substance in applications such as clinical analysis, environmental control and industrial pro- ... anisms could be optical (measure the deflection), or measurement of a change in ... point of care (PoC), and the instrumentation involved is quite sophisticated.

  10. Damage progression in silicon nitride undergoing non-conforming hybrid cyclic contact

    Czech Academy of Sciences Publication Activity Database

    Raga, R.; Khader, I.; Chlup, Zdeněk; Kailer, A.

    2017-01-01

    Roč. 105, DEC (2017), s. 97-110 ISSN 0142-1123 EU Projects: European Commission(XE) 263476 - ROLICER Institutional support: RVO:68081723 Keywords : Silicon nitride * Cyclic contact fatigue * Surface and subsurface damage Subject RIV: JL - Materials Fatigue, Friction Mechanics OBOR OECD: Audio engineering, reliability analysis Impact factor: 2.899, year: 2016

  11. Evaluation and silicon nitride internal combustion engine components. Final report, Phase I

    Energy Technology Data Exchange (ETDEWEB)

    Voldrich, W. [Allied-Signal Aerospace Co., Torrance, CA (United States). Garrett Ceramic Components Div.

    1992-04-01

    The feasibility of silicon nitride (Si{sub 3}N{sub 4}) use in internal combustion engines was studied by testing three different components for wear resistance and lower reciprocating mass. The information obtained from these preliminary spin rig and engine tests indicates several design changes are necessary to survive high-stress engine applications. The three silicon nitride components tested were valve spring retainers, tappet rollers, and fuel pump push rod ends. Garrett Ceramic Components` gas-pressure sinterable Si{sub 3}N{sub 4} (GS-44) was used to fabricate the above components. Components were final machined from densified blanks that had been green formed by isostatic pressing of GS-44 granules. Spin rig testing of the valve spring retainers indicated that these Si{sub 3}N{sub 4} components could survive at high RPM levels (9,500) when teamed with silicon nitride valves and lower spring tension than standard titanium components. Silicon nitride tappet rollers showed no wear on roller O.D. or I.D. surfaces, steel axles and lifters; however, due to the uncrowned design of these particular rollers the cam lobes indicated wear after spin rig testing. Fuel pump push rod ends were successful at reducing wear on the cam lobe and rod end when tested on spin rigs and in real-world race applications.

  12. Covalent functionalization of silicon nitride surfaces for anti-biofouling and bioselective capture

    NARCIS (Netherlands)

    Nguyen, A.T.

    2011-01-01

    Microsieves – microengineered membranes – have been introduced in microfiltration technology as a new generation of inorganic membranes. The thin membranes are made of silicon nitride (SixN4), which gives the membranes outstanding features, such as chemical inertness and high mechanical

  13. Near-field optical microscope using a silicon-nitride probe

    NARCIS (Netherlands)

    van Hulst, N.F.; Moers, M.H.P.; Moers, M.H.P.; Noordman, O.F.J.; Noordman, O.F.J.; Tack, R.G.; Segerink, Franciscus B.; Bölger, B.; Bölger, B.

    1993-01-01

    Operation of an alternative near-field optical microscope is presented. The microscope uses a microfabricated silicon- nitride probe with integrated cantilever, as originally developed for force microscopy. The cantilever allows routine close contact near-field imaging o­n arbitrary surfaces without

  14. Processing development for ceramic structural components: the influence of a presintering of silicon on the final properties of reaction bonded silicon nitride. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    1982-03-01

    The influence of a presintering of silicon on the final properties of reaction bonded silicon nitride has been studied using scanning electron and optical microscopy, x-ray diffraction analysis, 4 pt. bend test, and mecury intrusion porosimetry. It has been shown that presintering at 1050/sup 0/C will not affect the final nitrided properties. At 1200/sup 0/C, the oxide layer is removed, promoting the formation of B-phase silicon nitride. Presintering at 1200/sup 0/C also results in compact weight loss due to the volatilization of silicon, and the formation of large pores which severely reduce nitrided strength. The development of the structure of sintered silicon compacts appears to involve a temperature gradient, with greater sintering observed near the surface.

  15. Light-induced enhancement of the minority carrier lifetime in boron-doped Czochralski silicon passivated by doped silicon nitride

    International Nuclear Information System (INIS)

    Wang, Hongzhe; Chen, Chao; Pan, Miao; Sun, Yiling; Yang, Xi

    2015-01-01

    Graphical abstract: - Highlights: • The phosphorus-doped SiN x with negative fixed charge was deposited by PECVD. • The increase of lifetime was observed on P-doped SiN x passivated Si under illumination. • The enhancement of lifetime was caused by the increase of negative fixed charges. - Abstract: This study reports a doubling of the effective minority carrier lifetime under light soaking conditions, observed in a boron-doped p-type Czochralski grown silicon wafer passivated by a phosphorus-doped silicon nitride thin film. The analysis of capacitance–voltage curves revealed that the fixed charge in this phosphorus-doped silicon nitride film was negative, which was unlike the well-known positive fixed charges observed in traditional undoped silicon nitride. The analysis results revealed that the enhancement phenomenon of minority carrier lifetime was caused by the abrupt increase in the density of negative fixed charge (from 7.2 × 10 11 to 1.2 × 10 12 cm −2 ) after light soaking.

  16. Synthesis of carbon nitride powder by selective etching of TiC0.3N0.7 in chlorine-containing atmosphere at moderate temperature

    International Nuclear Information System (INIS)

    Sui Jian; Lu Jinjun

    2010-01-01

    We reported the synthesis of carbon nitride powder by extracting titanium from single inorganic precursor TiC 0.3 N 0.7 in chlorine-containing atmosphere at ambient pressure and temperature not exceeding 500 deg. C. The TiC 0.3 N 0.7 crystalline structure acted as a template, supplying active carbon and nitrogen atoms for carbon nitride when it was destroyed in chlorination. X-ray diffraction data showed that the obtained carbon nitride powders were amorphous, which was in good agreement with transmission electron microscope analysis. The composition and structure of carbon nitride powders were analyzed by employing Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. Results indicated that disorder structure was most likely for the carbon nitride powders and the N content depended greatly on the chlorination temperature. Thermal analysis in flowing N 2 indicated that the mass loss started from 300 deg. C and the complete decomposition occurred at around 650 deg. C, confirming the low thermal stability of the carbon nitride material.

  17. Fabrication of novel AFM probe with high-aspect-ratio ultra-sharp three-face silicon nitride tips

    NARCIS (Netherlands)

    Vermeer, Rolf; Berenschot, Johan W.; Sarajlic, Edin; Tas, Niels Roelof; Jansen, Henricus V.

    In this paper we present the wafer-scale fabrication of molded AFM probes with high aspect ratio ultra-sharp three-plane silicon nitride tips. Using $\\langle$111$\\rangle$ silicon wafers a dedicated process is developed to fabricate molds in the silicon wafer that have a flat triangular bottom

  18. Rolling-element fatigue life of silicon nitride balls. [as compared to that of steel, ceramic, and cermet materials

    Science.gov (United States)

    Parker, R. J.; Zaretsky, E. V.

    1974-01-01

    The five-ball fatigue tester was used to evaluate silicon nitride as a rolling-element bearing material. Results indicate that hot-pressed silicon nitride running against steel may be expected to yield fatigue lives comparable to or greater than those of bearing quality steel running against steel at stress levels typical rolling-element bearing application. The fatigue life of hot-pressed silicon nitride is considerably greater than that of any ceramic or cermet tested. Computer analysis indicates that there is no improvement in the lives of 120-mm-bore angular--contact ball bearings of the same geometry operating at DN values from 2 to 4 million where hot-pressed silicon nitride balls are used in place of steel balls.

  19. Study of the main parameters involved in carbothermal reduction reaction of silica aiming to obtain silicon nitride powder

    International Nuclear Information System (INIS)

    Rocha, J.C. da; Greca, M.C.

    1989-01-01

    The influence of main parameters involved in the method of silicon nitride attainment by carbothermal reduction of silica followed by nitridation were studied in isothermal experiments of fine powder mixtures of silica and graphite in a nitrogen gas flow. The time, temperature, rate C/SiO 2 and flow of nitrogen were varied since they are the main parameters involved in this kind of reaction. The products of reaction were analysed by X-ray diffraction to identify the crystalline phases and as a result was obtained the nucleation of silicon nitride phase. Meanwhile, corroborating prior results, we verified to be difficult the progress of the reaction and the inhibition of formation of silicon carbide phase, the last one being associated to the formation of silicon nitride phase due to thermodynamic matters [pt

  20. Heterogeneous integration of lithium niobate and silicon nitride waveguides for wafer-scale photonic integrated circuits on silicon.

    Science.gov (United States)

    Chang, Lin; Pfeiffer, Martin H P; Volet, Nicolas; Zervas, Michael; Peters, Jon D; Manganelli, Costanza L; Stanton, Eric J; Li, Yifei; Kippenberg, Tobias J; Bowers, John E

    2017-02-15

    An ideal photonic integrated circuit for nonlinear photonic applications requires high optical nonlinearities and low loss. This work demonstrates a heterogeneous platform by bonding lithium niobate (LN) thin films onto a silicon nitride (Si3N4) waveguide layer on silicon. It not only provides large second- and third-order nonlinear coefficients, but also shows low propagation loss in both the Si3N4 and the LN-Si3N4 waveguides. The tapers enable low-loss-mode transitions between these two waveguides. This platform is essential for various on-chip applications, e.g., modulators, frequency conversions, and quantum communications.

  1. Linear and nonlinear characterization of low-stress high-confinement silicon-rich nitride waveguides.

    Science.gov (United States)

    Krückel, Clemens J; Fülöp, Attila; Klintberg, Thomas; Bengtsson, Jörgen; Andrekson, Peter A; Torres-Company, Víctor

    2015-10-05

    In this paper we introduce a low-stress silicon enriched nitride platform that has potential for nonlinear and highly integrated optics. The manufacturing process of this platform is CMOS compatible and the increased silicon content allows tensile stress reduction and crack free layer growth of 700 nm. Additional benefits of the silicon enriched nitride is a measured nonlinear Kerr coefficient n(2) of 1.4·10(-18) m(2)/W (5 times higher than stoichiometric silicon nitride) and a refractive index of 2.1 at 1550 nm that enables high optical field confinement allowing high intensity nonlinear optics and light guidance even with small bending radii. We analyze the waveguide loss (∼1 dB/cm) in a spectrally resolved fashion and include scattering loss simulations based on waveguide surface roughness measurements. Detailed simulations show the possibility for fine dispersion and nonlinear engineering. In nonlinear experiments we present continuous-wave wavelength conversion and demonstrate that the material does not show nonlinear absorption effects. Finally, we demonstrate microfabrication of resonators with high Q-factors (∼10(5)).

  2. Structure analysis of aluminium silicon manganese nitride precipitates formed in grain-oriented electrical steels

    International Nuclear Information System (INIS)

    Bernier, Nicolas; Xhoffer, Chris; Van De Putte, Tom; Galceran, Montserrat; Godet, Stéphane

    2013-01-01

    We report a detailed structural and chemical characterisation of aluminium silicon manganese nitrides that act as grain growth inhibitors in industrially processed grain-oriented (GO) electrical steels. The compounds are characterised using energy dispersive X-ray spectrometry (EDX) and energy filtered transmission electron microscopy (EFTEM), while their crystal structures are analysed using X-ray diffraction (XRD) and TEM in electron diffraction (ED), dark-field, high-resolution and automated crystallographic orientation mapping (ACOM) modes. The chemical bonding character is determined using electron energy loss spectroscopy (EELS). Despite the wide variation in composition, all the precipitates exhibit a hexagonal close-packed (h.c.p.) crystal structure and lattice parameters of aluminium nitride. The EDX measurement of ∼ 900 stoichiometrically different precipitates indicates intermediate structures between pure aluminium nitride and pure silicon manganese nitride, with a constant Si/Mn atomic ratio of ∼ 4. It is demonstrated that aluminium and silicon are interchangeably precipitated with the same local arrangement, while both Mn 2+ and Mn 3+ are incorporated in the h.c.p. silicon nitride interstitial sites. The oxidation of the silicon manganese nitrides most likely originates from the incorporation of oxygen during the decarburisation annealing process, thus creating extended planar defects such as stacking faults and inversion domain boundaries. The chemical composition of the inhibitors may be written as (AlN) x (SiMn 0.25 N y O z ) 1−x with x ranging from 0 to 1. - Highlights: • We study the structure of (Al,Si,Mn)N inhibitors in grain oriented electrical steels. • Inhibitors have the hexagonal close-packed symmetry with lattice parameters of AlN. • Inhibitors are intermediate structures between pure AlN and (Si,Mn)N with Si/Mn ∼ 4. • Al and Si share the same local arrangement; Mn is incorporated in both Mn 2+ and Mn 3+ . • Oxygen

  3. Spin transport, magnetoresistance, and electrically detected magnetic resonance in amorphous hydrogenated silicon nitride

    Energy Technology Data Exchange (ETDEWEB)

    Mutch, Michael J. [Intercollege Program of Materials, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Lenahan, Patrick M. [Intercollege Program of Materials, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); King, Sean W. [Logic Technology Development, Intel Corporation, Hillsboro, Oregon 97124 (United States)

    2016-08-08

    We report on a study of spin transport via electrically detected magnetic resonance (EDMR) and near-zero field magnetoresistance (MR) in silicon nitride films. Silicon nitrides have long been important materials in solid state electronics. Although electronic transport in these materials is not well understood, electron paramagnetic resonance studies have identified a single dominating paramagnetic defect and have also provided physical and chemical descriptions of the defects, called K centers. Our EDMR and MR measurements clearly link the near-zero field MR response to the K centers and also indicate that K center energy levels are approximately 3.1 eV above the a-SiN:H valence band edge. In addition, our results suggest an approach for the study of defect mediated spin-transport in inorganic amorphous insulators via variable electric field and variable frequency EDMR and MR which may be widely applicable.

  4. Laser-assisted turning of components made of silicon-nitride ceramics

    International Nuclear Information System (INIS)

    Klocke, F.; Bausch, S.

    2001-01-01

    The manufacture of high-precision parts made of silicon-nitride ceramic, such as roller bearing rings or valves, currently involves finishing in the form of time and cost intensive grinding operations. This has resulted in demands for the development of more efficient machining techniques and for the subsequent provision of these within a manufacturing environment. A prototype of a precision lathe with an integrated high power diode laser for laser-assisted turning has been developed at the Fraunhofer IPT in close co-operation with industrial partners. When the workpiece is heated continuously by the laser, the resultant localized material softening enables the ceramic to be machined using a defined cutting edge. The application of this technique allows complex silicon nitride ceramic parts with surface qualities of up to R a = 0.3 μm to be produced considerably more flexibly than before, with no requirement for cooling lubricant. (author)

  5. Practical application of silicon nitride ceramics for sliding parts of rotary engine

    International Nuclear Information System (INIS)

    Ueki, M.; Sato, Y.; Fukuda, K.

    1994-01-01

    Research on ceramic substitutes for the apex seals of the rotary engine have been carrying out. The aim of the substitution of apex seals, the development of high strength silicon nitride ceramics, and the application of the ceramic to the apex seals are described. The properties of silicon nitride ceramics used as apex seals in rotary engines for racing cars are presented. The apex seals were recovered from the rotary engines of racing cars in the 1989 and 1990 Le Mans 24-hour Grand Prix races, and the damage of the seals was investigated and analyzed in detail. One problem was the adhesion to the seals of the hardened chromium plating detached from the inside surface of the rotor housing. The adhesion of chromium caused the fine cracking and subsequent chipping of the apex seals. (orig.)

  6. Application of Silicon Nitride (Si3N4 Ceramics in Ball Bearing

    Directory of Open Access Journals (Sweden)

    Wijianto Wijianto

    2016-08-01

    operation up to 1000°C, greater thermal shock resistance, lower density and low thermal expansion. This properties gives some benefit for ball bearing material such as higher running speed, reduce vibration of the shaft, will improve the life time and maintenance cost, lower heat generated, less energy consumption, lower wear rate, reducing noise level and reduce of using lubricant. The sintering methods are used to produce ball bearing from silicon nitride. Some techniques can be applied to increase ceramics strength which are reduce porosity, reduce grain size, reduce surface flaw and proof stressing. The surface finishing of the ceramic bearing is very important because silicon nitride as a brittle material, its strength is limited to the flaw sizes especially the flaw at the surface.

  7. Hydrogenated amorphous silicon nitride photonic crystals for improved-performance surface electromagnetic wave biosensors.

    Science.gov (United States)

    Sinibaldi, Alberto; Descrovi, Emiliano; Giorgis, Fabrizio; Dominici, Lorenzo; Ballarini, Mirko; Mandracci, Pietro; Danz, Norbert; Michelotti, Francesco

    2012-10-01

    We exploit the properties of surface electromagnetic waves propagating at the surface of finite one dimensional photonic crystals to improve the performance of optical biosensors with respect to the standard surface plasmon resonance approach. We demonstrate that the hydrogenated amorphous silicon nitride technology is a versatile platform for fabricating one dimensional photonic crystals with any desirable design and operating in a wide wavelength range, from the visible to the near infrared. We prepared sensors based on photonic crystals sustaining either guided modes or surface electromagnetic waves, also known as Bloch surface waves. We carried out for the first time a direct experimental comparison of their sensitivity and figure of merit with surface plasmon polaritons on metal layers, by making use of a commercial surface plasmon resonance instrument that was slightly adapted for the experiments. Our measurements demonstrate that the Bloch surface waves on silicon nitride photonic crystals outperform surface plasmon polaritons by a factor 1.3 in terms of figure of merit.

  8. Ultra-thin alumina and silicon nitride MEMS fabricated membranes for the electron multiplication

    Science.gov (United States)

    Prodanović, V.; Chan, H. W.; Graaf, H. V. D.; Sarro, P. M.

    2018-04-01

    In this paper we demonstrate the fabrication of large arrays of ultrathin freestanding membranes (tynodes) for application in a timed photon counter (TiPC), a novel photomultiplier for single electron detection. Low pressure chemical vapour deposited silicon nitride (Si x N y ) and atomic layer deposited alumina (Al2O3) with thicknesses down to only 5 nm are employed for the membrane fabrication. Detailed characterization of structural, mechanical and chemical properties of the utilized films is carried out for different process conditions and thicknesses. Furthermore, the performance of the tynodes is investigated in terms of secondary electron emission, a fundamental attribute that determines their applicability in TiPC. Studied features and presented fabrication methods may be of interest for other MEMS application of alumina and silicon nitride as well, in particular where strong ultra-thin membranes are required.

  9. Effects of plasma-deposited silicon nitride passivation on the radiation hardness of CMOS integrated circuits

    International Nuclear Information System (INIS)

    Clement, J.J.

    1980-01-01

    The use of plasma-deposited silicon nitride as a final passivation over metal-gate CMOS integrated circuits degrades the radiation hardness of these devices. The hardness degradation is manifested by increased radiation-induced threshold voltage shifts caused principally by the charging of new interface states and, to a lesser extent, by the trapping of holes created upon exposure to ionizing radiation. The threshold voltage shifts are a strong function of the deposition temperature, and show very little dependence on thickness for films deposited at 300 0 C. There is some correlation between the threshold voltage shifts and the hydrogen content of the PECVD silicon nitride films used as the final passivation layer as a function of deposition temperature. The mechanism by which the hydrogen contained in these films may react with the Si/SiO 2 interface is not clear at this point

  10. Microencapsulation of silicon nitride particles with yttria and yttria-alumina precursors

    International Nuclear Information System (INIS)

    Garg, A.K.; De Jonghe, L.C.

    1990-01-01

    Procedures are described to deposit uniform layers of yttria and yttria-alumina precursors on fine powders and whiskers of silicon nitride. The coatings were produced by aging at elevated temperatures aqueous systems containing the silicon nitride core particles, yttrium and aluminum nitrates, and urea. Optimum concentrations of the core particles, in relation to the reactants, were established to promote surface deposition of the oxide precursors. Polymeric dispersants were used effectively to prevent agglomeration of the solids during the microencapsulation process. The morphology of the powders was characterized using scanning and transmission electron microscopy. The mechanisms for the formation of the coated layers are discussed. A description is provided that allows qualitative assessment of the experimental factors that determine microencapsulation by a slurry method

  11. Robust Environmental Barrier Coatings for Silicon Nitride, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Silicon based ceramics are the leading candidates for the high temperature structural components of the advanced propulsion engines. For such applications, one key...

  12. Synthesis and characterization of nano silicon and titanium nitride ...

    Indian Academy of Sciences (India)

    The characterization techniques indicated ... Scalable synthesis; microwave plasma; chemical synthesis; nanoparticles. 1. Introduction ... used but very few methods are available to produce silicon and titanium ... current (A). (m3/h). 1. Si. 2.1.

  13. Strength evaluation test of pressureless-sintered silicon nitride at room temperature

    Science.gov (United States)

    Matsusue, K.; Takahara, K.; Hashimoto, R.

    1984-01-01

    In order to study strength characteristics at room temperature and the strength evaluating method of ceramic materials, the following tests were conducted on pressureless sintered silicon nitride specimens: bending tests, the three tensile tests of rectangular plates, holed plates, and notched plates, and spin tests of centrally holed disks. The relationship between the mean strength of specimens and the effective volume of specimens are examined using Weibull's theory. The effect of surface grinding on the strength of specimens is discussed.

  14. The Effects of Thermal Cycling on Gallium Nitride and Silicon Carbide Semiconductor Devices for Aerospace Use

    Science.gov (United States)

    Patterson, Richard L.; Hammoud, Ahmad

    2012-01-01

    Electronics designed for use in NASA space missions are required to work efficiently and reliably under harsh environment conditions. These Include radiation, extreme temperatures, thermal cycling, to name a few. Preliminary data obtained on new Gallium Nitride and Silicon Carbide power devices under exposure to radiation followed by long term thermal cycling are presented. This work was done in collaboration with GSFC and JPL in support of the NASA Electronic Parts and Packaging (NEPP) Program

  15. Effect of hot isostatic pressing on reaction-bonded silicon nitride

    Science.gov (United States)

    Watson, G. K.; Moore, T. J.; Millard, M. L.

    1984-01-01

    Specimens of nearly theoretical density have been obtained through the isostatic hot pressing of reaction-bonded silicon nitride under 138 MPa of pressure for two hours at 1850, 1950, and 2050 C. An amorphous phase that is introduced by the hot isostatic pressing partly accounts for the fact that while room temperature flexural strength more than doubles, the 1200 C flexural strength increases significantly only after pressing at 2050 C.

  16. Highly nonlinear sub-micron silicon nitride trench waveguide coated with gold nanoparticles

    Science.gov (United States)

    Huang, Yuewang; Zhao, Qiancheng; Sharac, Nicholas; Ragan, Regina; Boyraz, Ozdal

    2015-05-01

    We demonstrate the fabrication of a highly nonlinear sub-micron silicon nitride trench waveguide coated with gold nanoparticles for plasmonic enhancement. The average enhancement effect is evaluated by measuring the spectral broadening effect caused by self-phase-modulation. The nonlinear refractive index n2 was measured to be 7.0917×10-19 m2/W for a waveguide whose Wopen is 5 μm. Several waveguides at different locations on one wafer were measured in order to take the randomness of the nanoparticle distribution into consideration. The largest enhancement is measured to be as high as 10 times. Fabrication of this waveguide started with a MEMS grade photomask. By using conventional optical lithography, the wide linewidth was transferred to a wafer. Then the wafer was etched anisotropically by potassium hydroxide (KOH) to engrave trapezoidal trenches with an angle of 54.7º. Side wall roughness was mitigated by KOH etching and thermal oxidation that was used to generate a buffer layer for silicon nitride waveguide. The guiding material silicon nitride was then deposited by low pressure chemical vapor deposition. The waveguide was then patterned with a chemical template, with 20 nm gold particles being chemically attached to the functionalized poly(methyl methacrylate) domains. Since the particles attached only to the PMMA domains, they were confined to localized regions, therefore forcing the nanoparticles into clusters of various numbers and geometries. Experiments reveal that the waveguide has negligible nonlinear absorption loss, and its nonlinear refractive index can be greatly enhanced by gold nano clusters. The silicon nitride trench waveguide has large nonlinear refractive index, rendering itself promising for nonlinear applications.

  17. Dispersion engineering of thick high-Q silicon nitride ring-resonators via atomic layer deposition.

    Science.gov (United States)

    Riemensberger, Johann; Hartinger, Klaus; Herr, Tobias; Brasch, Victor; Holzwarth, Ronald; Kippenberg, Tobias J

    2012-12-03

    We demonstrate dispersion engineering of integrated silicon nitride based ring resonators through conformal coating with hafnium dioxide deposited on top of the structures via atomic layer deposition. Both, magnitude and bandwidth of anomalous dispersion can be significantly increased. The results are confirmed by high resolution frequency-comb-assisted-diode-laser spectroscopy and are in very good agreement with the simulated modification of the mode spectrum.

  18. Analysis of the effective thermoelastic properties and stress fields in silicon nitride based on EBSD data

    Czech Academy of Sciences Publication Activity Database

    Othmani, Y.; Böhlke, T.; Lube, T.; Fellmeth, A.; Chlup, Zdeněk; Colonna, F.; Hashibon, A.

    2016-01-01

    Roč. 36, č. 5 (2016), s. 1109-1125 ISSN 0955-2219 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068 EU Projects: European Commission(XE) 263476 Institutional support: RVO:68081723 Keywords : Silicon nitride * EBSD data * Hashin-Shtrikman bounds * Finite element analysis Subject RIV: JH - Ceramic s, Fire-Resistant Materials and Glass Impact factor: 3.411, year: 2016

  19. Rf-plasma synthesis of nanosize silicon carbide and nitride. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Buss, R.J.

    1997-02-01

    A pulsed rf plasma technique is capable of generating ceramic particles of 10 manometer dimension. Experiments using silane/ammonia and trimethylchlorosilane/hydrogen gas mixtures show that both silicon nitride and silicon carbide powders can be synthesized with control of the average particle diameter from 7 to 200 nm. Large size dispersion and much agglomeration appear characteristic of the method, in contrast to results reported by another research group. The as produced powders have a high hydrogen content and are air and moisture sensitive. Post-plasma treatment in a controlled atmosphere at elevated temperature (800{degrees}C) eliminates the hydrogen and stabilizes the powder with respect to oxidation or hydrolysis.

  20. Mechanics of silicon nitride thin-film stressors on a transistor-like geometry

    Directory of Open Access Journals (Sweden)

    S. Reboh

    2013-10-01

    Full Text Available To understand the behavior of silicon nitride capping etch stopping layer stressors in nanoscale microelectronics devices, a simplified structure mimicking typical transistor geometries was studied. Elastic strains in the silicon substrate were mapped using dark-field electron holography. The results were interpreted with the aid of finite element method modeling. We show, in a counterintuitive sense, that the stresses developed by the film in the vertical sections around the transistor gate can reach much higher values than the full sheet reference. This is an important insight for advanced technology nodes where the vertical contribution of such liners is predominant over the horizontal part.

  1. Impedimetric immunosensor for human serum albumin detection on a direct aldehyde-functionalized silicon nitride surface

    Energy Technology Data Exchange (ETDEWEB)

    Caballero, David, E-mail: caballero@unistra.fr [Nanobioengineering group-IBEC, Barcelona Science Park, C/ Baldiri Reixach 10-12, 08028 Barcelona (Spain); University of Barcelona, Department of Electronics, C/ Marti i Franques 1, 08028 Barcelona (Spain); Centro de Investigacion Biomedica en Red en Bioingenieria, Biomateriales y Nanomedicina (CIBER-BBN), 50018 Zaragoza (Spain); Martinez, Elena [Nanobioengineering group-IBEC, Barcelona Science Park, C/ Baldiri Reixach 10-12, 08028 Barcelona (Spain); Centro de Investigacion Biomedica en Red en Bioingenieria, Biomateriales y Nanomedicina (CIBER-BBN), 50018 Zaragoza (Spain); Bausells, Joan [Centre Nacional de Microelectronica (CNM-IMB), CSIC, Campus UAB, 08193 Bellaterra (Spain); Errachid, Abdelhamid, E-mail: abdelhamid.errachid-el-salhi@univ-lyon1.fr [Nanobioengineering group-IBEC, Barcelona Science Park, C/ Baldiri Reixach 10-12, 08028 Barcelona (Spain); Universite Claude Bernard - Lyon 1, LSA - UMR 5180, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex (France); Samitier, Josep [Nanobioengineering group-IBEC, Barcelona Science Park, C/ Baldiri Reixach 10-12, 08028 Barcelona (Spain); University of Barcelona, Department of Electronics, C/ Marti i Franques 1, 08028 Barcelona (Spain); Centro de Investigacion Biomedica en Red en Bioingenieria, Biomateriales y Nanomedicina (CIBER-BBN), 50018 Zaragoza (Spain)

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer An impedimetric label-free immunosensor was developed for the specific detection of human serum albumin proteins. Black-Right-Pointing-Pointer Anti-HSA antibodies were covalently immobilized on silicon nitride surfaces using a direct functionalization methodology. Black-Right-Pointing-Pointer Silicon nitride offers multiple advantages compared to other common materials. Black-Right-Pointing-Pointer The proposed sensor has high sensitivity and good selectivity for the detection of HSA proteins. - Abstract: In this work we report the fabrication and characterization of a label-free impedimetric immunosensor based on a silicon nitride (Si{sub 3}N{sub 4}) surface for the specific detection of human serum albumin (HSA) proteins. Silicon nitride provides several advantages compared with other materials commonly used, such as gold, and in particular in solid-state physics for electronic-based biosensors. However, few Si{sub 3}N{sub 4}-based biosensors have been developed; the lack of an efficient and direct protocol for the integration of biological elements with silicon-based substrates is still one of its the main drawbacks. Here, we use a direct functionalization method for the direct covalent binding of monoclonal anti-HSA antibodies on an aldehyde-functionalized Si-p/SiO{sub 2}/Si{sub 3}N{sub 4} structure. This methodology, in contrast with most of the protocols reported in literature, requires less chemical reagents, it is less time-consuming and it does not need any chemical activation. The detection capability of the immunosensor was tested by performing non-faradaic electrochemical impedance spectroscopy (EIS) measurements for the specific detection of HSA proteins. Protein concentrations within the linear range of 10{sup -13}-10{sup -7} M were detected, showing a sensitivity of 0.128 {Omega} {mu}M{sup -1} and a limit of detection of 10{sup -14} M. The specificity of the sensor was also addressed by studying the

  2. Impedimetric immunosensor for human serum albumin detection on a direct aldehyde-functionalized silicon nitride surface

    International Nuclear Information System (INIS)

    Caballero, David; Martinez, Elena; Bausells, Joan; Errachid, Abdelhamid; Samitier, Josep

    2012-01-01

    Highlights: ► An impedimetric label-free immunosensor was developed for the specific detection of human serum albumin proteins. ► Anti-HSA antibodies were covalently immobilized on silicon nitride surfaces using a direct functionalization methodology. ► Silicon nitride offers multiple advantages compared to other common materials. ► The proposed sensor has high sensitivity and good selectivity for the detection of HSA proteins. - Abstract: In this work we report the fabrication and characterization of a label-free impedimetric immunosensor based on a silicon nitride (Si 3 N 4 ) surface for the specific detection of human serum albumin (HSA) proteins. Silicon nitride provides several advantages compared with other materials commonly used, such as gold, and in particular in solid-state physics for electronic-based biosensors. However, few Si 3 N 4 -based biosensors have been developed; the lack of an efficient and direct protocol for the integration of biological elements with silicon-based substrates is still one of its the main drawbacks. Here, we use a direct functionalization method for the direct covalent binding of monoclonal anti-HSA antibodies on an aldehyde-functionalized Si-p/SiO 2 /Si 3 N 4 structure. This methodology, in contrast with most of the protocols reported in literature, requires less chemical reagents, it is less time-consuming and it does not need any chemical activation. The detection capability of the immunosensor was tested by performing non-faradaic electrochemical impedance spectroscopy (EIS) measurements for the specific detection of HSA proteins. Protein concentrations within the linear range of 10 −13 –10 −7 M were detected, showing a sensitivity of 0.128 Ω μM −1 and a limit of detection of 10 −14 M. The specificity of the sensor was also addressed by studying the interferences with a similar protein, bovine serum albumin. The results obtained show that the antibodies were efficiently immobilized and the proteins

  3. Chlorine

    Science.gov (United States)

    ... your clothing, rapidly wash your entire body with soap and water, and get medical care as quickly as possible. Removing and disposing of clothing: Quickly take off clothing that has liquid chlorine on it. Any clothing that has to ...

  4. Fracture toughness of silicon nitride thin films of different thicknesses as measured by bulge tests

    International Nuclear Information System (INIS)

    Merle, B.; Goeken, M.

    2011-01-01

    A bulge test setup was used to determine the fracture toughness of amorphous low-pressure chemical vapor deposited (LPCVD) silicon nitride films with various thicknesses in the range 40-108 nm. A crack-like slit was milled in the center of each free-standing film with a focused ion beam, and the membrane was deformed in the bulge test until failure occurred. The fracture toughness K IC was calculated from the pre-crack length and the stress at failure. It is shown that the membrane is in a transition state between pure plane-stress and plane-strain which, however, had a negligible influence on the measurement of the fracture toughness, because of the high brittleness of silicon nitride and its low Young's modulus over yield strength ratio. The fracture toughness K IC was found to be constant at 6.3 ± 0.4 MPa m 1/2 over the whole thickness range studied, which compares well with bulk values. This means that the fracture toughness, like the Young's modulus, is a size-independent quantity for LPCVD silicon nitride. This presumably holds true for all amorphous brittle ceramic materials.

  5. Tantalum Nitride Electron-Selective Contact for Crystalline Silicon Solar Cells

    KAUST Repository

    Yang, Xinbo

    2018-04-19

    Minimizing carrier recombination at contact regions by using carrier‐selective contact materials, instead of heavily doping the silicon, has attracted considerable attention for high‐efficiency, low‐cost crystalline silicon (c‐Si) solar cells. A novel electron‐selective, passivating contact for c‐Si solar cells is presented. Tantalum nitride (TaN x ) thin films deposited by atomic layer deposition are demonstrated to provide excellent electron‐transporting and hole‐blocking properties to the silicon surface, due to their small conduction band offset and large valence band offset. Thin TaNx interlayers provide moderate passivation of the silicon surfaces while simultaneously allowing a low contact resistivity to n‐type silicon. A power conversion efficiency (PCE) of over 20% is demonstrated with c‐Si solar cells featuring a simple full‐area electron‐selective TaNx contact, which significantly improves the fill factor and the open circuit voltage (Voc) and hence provides the higher PCE. The work opens up the possibility of using metal nitrides, instead of metal oxides, as carrier‐selective contacts or electron transport layers for photovoltaic devices.

  6. Formation of Mach angle profiles during wet etching of silica and silicon nitride materials

    Energy Technology Data Exchange (ETDEWEB)

    Ghulinyan, M., E-mail: ghulinyan@fbk.eu [Centre for Materials and Microsystems, Fondazione Bruno Kessler, I-38123 Povo (Italy); Bernard, M.; Bartali, R. [Centre for Materials and Microsystems, Fondazione Bruno Kessler, I-38123 Povo (Italy); Deptartment of Physics, University of Trento, I-38123 Povo (Italy); Pucker, G. [Centre for Materials and Microsystems, Fondazione Bruno Kessler, I-38123 Povo (Italy)

    2015-12-30

    Highlights: • Photoresist adhesion induces the formation of complex etch profiles in dielectrics. • Hydrofluoric acid etching of silica glass and silicon nitride materials was studied. • The phenomenon has been modeled in analogy with sonic boom propagation. • The material etch rate and resist adhesion/erosion define the final profile. - Abstract: In integrated circuit technology peeling of masking photoresist films is a major drawback during the long-timed wet etching of materials. It causes an undesired film underetching, which is often accompanied by a formation of complex etch profiles. Here we report on a detailed study of wedge-shaped profile formation in a series of silicon oxide, silicon oxynitride and silicon nitride materials during wet etching in a buffered hydrofluoric acid (BHF) solution. The shape of etched profiles reflects the time-dependent adhesion properties of the photoresist to a particular material and can be perfectly circular, purely linear or a combination of both, separated by a knee feature. Starting from a formal analogy between the sonic boom propagation and the wet underetching process, we model the wedge formation mechanism analytically. This model predicts the final form of the profile as a function of time and fits the experimental data perfectly. We discuss how this knowledge can be extended to the design and the realization of optical components such as highly efficient etch-less vertical tapers for passive silicon photonics.

  7. Optical and passivating properties of hydrogenated amorphous silicon nitride deposited by plasma enhanced chemical vapour deposition for application on silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Wight, Daniel Nilsen

    2008-07-01

    Within this thesis, several important subjects related to the use of amorphous silicon nitride made by plasma enhanced chemical vapour deposition as an anti-reflective coating on silicon solar cells are presented. The first part of the thesis covers optical simulations to optimise single and double layer anti-reflective coatings with respect to optical performance when situated on a silicon solar cell. The second part investigates the relationship between important physical properties of silicon nitride films when deposited under different conditions. The optical simulations were either based on minimising the reflectance off a silicon nitride/silicon wafer stack or maximising the transmittance through the silicon nitride into the silicon wafer. The former method allowed consideration of the reflectance off the back surface of the wafer, which occurs typically at wavelengths above 1000 nm due to the transparency of silicon at these wavelengths. However, this method does not take into consideration the absorption occurring in the silicon nitride, which is negligible at low refractive indexes but quite significant when the refractive index increases above 2.1. For high-index silicon nitride films, the latter method is more accurate as it considers both reflectance and absorbance in the film to calculate the transmittance into the Si wafer. Both methods reach similar values for film thickness and refractive index for optimised single layer anti-reflective coatings, due to the negligible absorption occurring in these films. For double layer coatings, though, the reflectance based simulations overestimated the optimum refractive index for the bottom layer, which would have lead to excessive absorption if applied to real anti-reflective coatings. The experimental study on physical properties for silicon nitride films deposited under varying conditions concentrated on the estimation of properties important for its applications, such as optical properties, passivation

  8. Atomic oxygen effects on boron nitride and silicon nitride: A comparison of ground based and space flight data

    Science.gov (United States)

    Cross, J. B.; Lan, E. H.; Smith, C. A.; Whatley, W. J.

    1990-01-01

    The effects of atomic oxygen on boron nitride (BN) and silicon nitride (Si3N4) were evaluated in a low Earth orbit (LEO) flight experiment and in a ground based simulation facility. In both the inflight and ground based experiments, these materials were coated on thin (approx. 250A) silver films, and the electrical resistance of the silver was measured in situ to detect any penetration of atomic oxygen through the BN and Si3N4 materials. In the presence of atomic oxygen, silver oxidizes to form silver oxide, which has a much higher electrical resistance than pure silver. Permeation of atomic oxygen through BN, as indicated by an increase in the electrical resistance of the silver underneath, was observed in both the inflight and ground based experiments. In contrast, no permeation of atomic oxygen through Si3N4 was observed in either the inflight or ground based experiments. The ground based results show good qualitative correlation with the LEO flight results, indicating that ground based facilities such as the one at Los Alamos National Lab can reproduce space flight data from LEO.

  9. Deformation and wear of pyramidal, silicon-nitride AFM tips scanning micrometre-size features in contact mode

    NARCIS (Netherlands)

    Bloo, M.; Haitjema, H.; Pril, W.O.

    1999-01-01

    An experimental study was carried out, in order to investigate the deformation and wear taking place on pyramidal silicon-nitride AFM tips. The study focuses on the contact mode scanning of silicon features of micrometre-size. First the deformation and the mechanisms of wear of the tip during

  10. Damage-free laser patterning of silicon nitride on textured crystalline silicon using an amorphous silicon etch mask for Ni/Cu plated silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Bailly, Mark S., E-mail: mbailly@asu.edu; Karas, Joseph; Jain, Harsh; Dauksher, William J.; Bowden, Stuart

    2016-08-01

    We investigate the optimization of laser ablation with a femtosecond laser for direct and indirect removal of SiN{sub x} on alkaline textured c-Si. Our proposed resist-free indirect removal process uses an a-Si:H etch mask and is demonstrated to have a drastically improved surface quality of the laser processed areas when compared to our direct removal process. Scanning electron microscope images of ablated sites show the existence of substantial surface defects for the standard direct removal process, and the reduction of those defects with our proposed process. Opening of SiN{sub x} and SiO{sub x} passivating layers with laser ablation is a promising alternative to the standard screen print and fire process for making contact to Si solar cells. The potential for small contacts from laser openings of dielectrics coupled with the selective deposition of metal from light induced plating allows for high-aspect-ratio metal contacts for front grid metallization. The minimization of defects generated in this process would serve to enhance the performance of the device and provides the motivation for our work. - Highlights: • Direct laser removal of silicon nitride (SiN{sub x}) damages textured silicon. • Direct laser removal of amorphous silicon (a-Si) does not damage textured silicon. • a-Si can be used as a laser patterned etch mask for SiN{sub x}. • Chemically patterned SiN{sub x} sites allow for Ni/Cu plating.

  11. Silicon structuring by etching with liquid chlorine and fluorine precursors using femtosecond laser pulses

    International Nuclear Information System (INIS)

    Radu, C.; Simion, S.; Zamfirescu, M.; Ulmeanu, M.; Enculescu, M.; Radoiu, M.

    2011-01-01

    The aim of this study is to investigate the micrometer and submicrometer scale structuring of silicon by liquid chlorine and fluorine precursors with 200 fs laser pulses working at both fundamental (775 nm) and frequency doubled (387 nm) wavelengths. The silicon surface was irradiated at normal incidence by immersing the Si (111) substrates in a glass container filled with liquid chlorine (CCl 4 ) and fluorine (C 2 Cl 3 F 3 ) precursors. We report that silicon surfaces develop an array of spikes with single step irradiation processes at 775 nm and equally at 387 nm. When irradiating the Si surface with 400 pulses at 330 mJ/cm 2 laser fluence and a 775 nm wavelength, the average height of the formed Si spikes in the case of fluorine precursors is 4.2 μm, with a full width at half maximum of 890 nm. At the same irradiation wavelength chlorine precursors develop Si spikes 4 μm in height and with a full width at half maximum of 2.3 μm with irradiation of 700 pulses at 560 mJ/cm 2 laser fluence. Well ordered areas of submicrometer spikes with an average height of about 500 nm and a width of 300 nm have been created by irradiation at 387 nm by chlorine precursors, whereas the fluorine precursors fabricate spikes with an average height of 700 nm and a width of about 200 nm. Atomic force microscopy and scanning electron microscopy of the surface show that the formation of the micrometer and sub-micrometer spikes involves a combination of capillary waves on the molten silicon surface and laser-induced etching of silicon, at both 775 nm and 387 nm wavelength irradiation. The energy-dispersive x-ray measurements indicate the presence of chlorine and fluorine precursors on the structured surface. The fluorine precursors create a more ordered area of Si spikes at both micrometer and sub-micrometer scales. The potential use of patterned Si substrates with gradient topography as model scaffolds for the systematic exploration of the role of 3D micro/nano morphology on cell

  12. Power mixture and green body for producing silicon nitride base articles of high fracture toughness and strength

    Science.gov (United States)

    Huckabee, M.L.; Buljan, S.T.; Neil, J.T.

    1991-09-17

    A powder mixture and a green body for producing a silicon nitride-based article of improved fracture toughness and strength are disclosed. The powder mixture includes (a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon nitride powder of an average particle size of about 0.2 [mu]m and a surface area of about 8-12m[sup 2]g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 [mu]m and a surface area of about 2-4 m[sup 2]/g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified article an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. The green body is formed from the powder mixture, an effective amount of a suitable oxide densification aid, and an effective amount of a suitable organic binder. No Drawings

  13. Silicon nitride gradient film as the underlayer of ultra-thin tetrahedral amorphous carbon overcoat for magnetic recording slider

    Energy Technology Data Exchange (ETDEWEB)

    Wang Guigen, E-mail: wanggghit@yahoo.com [Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen 518055 (China); Kuang Xuping; Zhang Huayu; Zhu Can [Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen 518055 (China); Han Jiecai [Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen 518055 (China); Center for Composite Materials, Harbin Institute of Technology, Harbin 150080 (China); Zuo Hongbo [Center for Composite Materials, Harbin Institute of Technology, Harbin 150080 (China); Ma Hongtao [SAE Technologies Development (Dongguan) Co., Ltd., Dongguan 523087 (China)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer The ultra-thin carbon films with different silicon nitride (Si-N) film underlayers were prepared. Black-Right-Pointing-Pointer It highlighted the influences of Si-N underlayers. Black-Right-Pointing-Pointer The carbon films with Si-N underlayers obtained by nitriding especially at the substrate bias of -150 V, can exhibit better corrosion protection properties - Abstract: There are higher technical requirements for protection overcoat of magnetic recording slider used in high-density storage fields for the future. In this study, silicon nitride (Si-N) composition-gradient films were firstly prepared by nitriding of silicon thin films pre-sputtered on silicon wafers and magnetic recording sliders, using microwave electron cyclotron resonance plasma source. The ultra-thin tetrahedral amorphous carbon films were then deposited on the Si-N films by filtered cathodic vacuum arc method. Compared with amorphous carbon overcoats with conventional silicon underlayers, the overcoats with Si-N underlayers obtained by plasma nitriding especially at the substrate bias of -150 V, can provide better corrosion protection for high-density magnetic recording sliders.

  14. Silicon nitride gradient film as the underlayer of ultra-thin tetrahedral amorphous carbon overcoat for magnetic recording slider

    International Nuclear Information System (INIS)

    Wang Guigen; Kuang Xuping; Zhang Huayu; Zhu Can; Han Jiecai; Zuo Hongbo; Ma Hongtao

    2011-01-01

    Highlights: ► The ultra-thin carbon films with different silicon nitride (Si-N) film underlayers were prepared. ► It highlighted the influences of Si-N underlayers. ► The carbon films with Si-N underlayers obtained by nitriding especially at the substrate bias of −150 V, can exhibit better corrosion protection properties - Abstract: There are higher technical requirements for protection overcoat of magnetic recording slider used in high-density storage fields for the future. In this study, silicon nitride (Si-N) composition-gradient films were firstly prepared by nitriding of silicon thin films pre-sputtered on silicon wafers and magnetic recording sliders, using microwave electron cyclotron resonance plasma source. The ultra-thin tetrahedral amorphous carbon films were then deposited on the Si-N films by filtered cathodic vacuum arc method. Compared with amorphous carbon overcoats with conventional silicon underlayers, the overcoats with Si-N underlayers obtained by plasma nitriding especially at the substrate bias of −150 V, can provide better corrosion protection for high-density magnetic recording sliders.

  15. Effect of additive gases and injection methods on chemical dry etching of silicon nitride, silicon oxynitride, and silicon oxide layers in F2 remote plasmas

    International Nuclear Information System (INIS)

    Yun, Y. B.; Park, S. M.; Kim, D. J.; Lee, N.-E.; Kim, K. S.; Bae, G. H.

    2007-01-01

    The authors investigated the effects of various additive gases and different injection methods on the chemical dry etching of silicon nitride, silicon oxynitride, and silicon oxide layers in F 2 remote plasmas. N 2 and N 2 +O 2 gases in the F 2 /Ar/N 2 and F 2 /Ar/N 2 /O 2 remote plasmas effectively increased the etch rate of the layers. The addition of direct-injected NO gas increased the etch rates most significantly. NO radicals generated by the addition of N 2 and N 2 +O 2 or direct-injected NO molecules contributed to the effective removal of nitrogen and oxygen in the silicon nitride and oxide layers, by forming N 2 O and NO 2 by-products, respectively, and thereby enhancing SiF 4 formation. As a result of the effective removal of the oxygen, nitrogen, and silicon atoms in the layers, the chemical dry etch rates were enhanced significantly. The process regime for the etch rate enhancement of the layers was extended at elevated temperature

  16. Formation of porous surface layers in reaction bonded silicon nitride during processing

    Science.gov (United States)

    Shaw, N. J.; Glasgow, T. K.

    1979-01-01

    Microstructural examination of reaction bonded silicon nitride (RBSN) has shown that there is often a region adjacent to the as-nitrided surfaces that is even more porous than the interior of this already quite porous material. Because this layer of large porosity is considered detrimental to both the strength and oxidation resistance of RBSN, a study was undertaken to determine if its formation could be prevented during processing. All test bars studied were made from a single batch of Si powder which was milled for 4 hours in heptane in a vibratory mill using high density alumina cylinders as the grinding media. After air drying the powder, bars were compacted in a single acting die and hydropressed.

  17. Study Trapped Charge Distribution in P-Channel Silicon-Oxide-Nitride-Oxide-Silicon Memory Device Using Dynamic Programming Scheme

    Science.gov (United States)

    Li, Fu-Hai; Chiu, Yung-Yueh; Lee, Yen-Hui; Chang, Ru-Wei; Yang, Bo-Jun; Sun, Wein-Town; Lee, Eric; Kuo, Chao-Wei; Shirota, Riichiro

    2013-04-01

    In this study, we precisely investigate the charge distribution in SiN layer by dynamic programming of channel hot hole induced hot electron injection (CHHIHE) in p-channel silicon-oxide-nitride-oxide-silicon (SONOS) memory device. In the dynamic programming scheme, gate voltage is increased as a staircase with fixed step amplitude, which can prohibits the injection of holes in SiN layer. Three-dimensional device simulation is calibrated and is compared with the measured programming characteristics. It is found, for the first time, that the hot electron injection point quickly traverses from drain to source side synchronizing to the expansion of charged area in SiN layer. As a result, the injected charges quickly spread over on the almost whole channel area uniformly during a short programming period, which will afford large tolerance against lateral trapped charge diffusion by baking.

  18. Direct comparison of the electrical properties in metal/oxide/nitride/oxide/silicon and metal/aluminum oxide/nitride/oxide/silicon capacitors with equivalent oxide thicknesses

    Energy Technology Data Exchange (ETDEWEB)

    An, Ho-Myoung; Seo, Yu Jeong; Kim, Hee Dong; Kim, Kyoung Chan; Kim, Jong-Guk [School of Electrical Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Cho, Won-Ju; Koh, Jung-Hyuk [Department of Electronic Materials Engineering, Kwangwoon University, Seoul 139-701 (Korea, Republic of); Sung, Yun Mo [Department of Materials and Science Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Kim, Tae Geun, E-mail: tgkim1@korea.ac.k [School of Electrical Engineering, Korea University, Seoul 136-713 (Korea, Republic of)

    2009-07-31

    We examine the electrical properties of metal/oxide/nitride/oxide/silicon (MONOS) capacitors with two different blocking oxides, SiO{sub 2} and Al{sub 2}O{sub 3}, under the influence of the same electric field. The thickness of the Al{sub 2}O{sub 3} layer is set to 150 A, which is electrically equivalent to a thickness of the SiO{sub 2} layer of 65 A, in the MONOS structure for this purpose. The capacitor with the Al{sub 2}O{sub 3} blocking layer shows a larger capacitance-voltage memory window of 8.6 V, lower program voltage of 7 V, faster program/erase speeds of 10 ms/1 {mu}s, lower leakage current of 100 pA and longer data retention than the one with the SiO{sub 2} blocking layer does. These improvements are attributed to the suppression of the carrier transport to the gate electrode afforded by the use of an Al{sub 2}O{sub 3} blocking layer physically thicker than the SiO{sub 2} one, as well as the effective charge-trapping by Al{sub 2}O{sub 3} at the deep energy levels in the nitride layer.

  19. Mechanical and tribological properties of silicon nitride films synthesized by ion beam enhanced deposition

    International Nuclear Information System (INIS)

    Chen Yuanru; Li Shizhuo; Zhang Xushou; Liu Hong; Yang Genqing; Qu Baochun

    1991-01-01

    This article describes preliminary investigations of mechanical and tribological properties of silicon nitride film formed by ion beam enhanced deposition (IBED) on GH37 (Ni-based alloys) steel. The films were synthesized by silicon vapor deposition with a rate of 1 A/s and by 40 keV nitrogen ion bombardment simultaneously. The thickness of the film was about 5000 A. X-ray photoelectron spectroscopy and infrared absorption spectroscopy revealed that a stoichiometric Si 3 N 4 film was formed. The observation of TEM showed that the IBED Si 3 N 4 film normally had an amorphous structure. However, electron diffraction patterns revealed a certain crystallinity. The mechanical and tribological properties of the films were investigated with a scratch tester, microhardness meter, and a ball-on-disc tribometer respectively. Results show that the adhesive strength between film and substrate is about 51 N, the Vickers microhardness with a load of 0.2 N is 980, the friction coefficient measured for steel against silicon nitride film ranges from 0.1 to 0.15, and the wear rate of coatings is about 6.8x10 -5 mm 3 /(mN). Finally, the relationship among thermal annealing, crystallinity and tribological characteristics of the Si 3 N 4 film is discussed. (orig.)

  20. Back scattering involving embedded silicon nitride (SiN) nanoparticles for c-Si solar cells

    Science.gov (United States)

    Ghosh, Hemanta; Mitra, Suchismita; Siddiqui, M. S.; Saxena, A. K.; Chaudhuri, Partha; Saha, Hiranmay; Banerjee, Chandan

    2018-04-01

    A novel material, structure and method of synthesis for dielectric light trapping have been presented in this paper. First, the light scattering behaviour of silicon nitride nanoparticles have been theoretically studied in order to find the optimized size for dielectric back scattering by FDTD simulations from Lumerical Inc. The optical results have been used in electrical analysis and thereby, estimate the effect of nanoparticles on efficiency of the solar cells depending on substrate thickness. Experimentally, silicon nitride (SiN) nanoparticles have been formed using hydrogen plasma treatment on SiN layer deposited by Plasma Enhanced Chemical Vapour Deposition (PECVD). The size and area coverage of the nanoparticles were controlled by varying the working pressure, power density and treatment duration. The nanoparticles were integrated with partial rear contact c-Si solar cells as dielectric back reflector structures for the light trapping in thin silicon solar cells. Experimental results revealed the increases of current density by 2.7% in presence of SiN nanoparticles.

  1. Characteristics of thin-film transistors based on silicon nitride passivation by excimer laser direct patterning

    International Nuclear Information System (INIS)

    Chen, Chao-Nan; Huang, Jung-Jie

    2013-01-01

    This study explored the removal of silicon nitride using KrF laser ablation technology with a high threshold fluence of 990 mJ/cm 2 . This technology was used for contact hole patterning to fabricate SiN x -passivation-based amorphous-silicon thin films in a transistor device. Compared to the photolithography process, laser direct patterning using KrF laser ablation technology can reduce the number of process steps by at least three. Experimental results showed that the mobility and threshold voltages of thin film transistors patterned using the laser process were 0.16 cm 2 /V-sec and 0.2 V, respectively. The device performance and the test results of gate voltage stress reliability demonstrated that laser direct patterning is a promising alternative to photolithography in the panel manufacturing of thin-film transistors for liquid crystal displays. - Highlights: ► KrF laser ablation technology is used to remove silicon nitride. ► A simple method for direct patterning contact-hole in thin-film-transistor device. ► Laser technology reduced processing by at least three steps

  2. Remote PECVD silicon nitride films with improved electrical properties for GaAs P-HEMT passivation

    CERN Document Server

    Sohn, M K; Kim, K H; Yang, S G; Seo, K S

    1998-01-01

    In order to obtain thin silicon nitride films with excellent electrical and mechanical properties, we employed RPECVD (Remote Plasma Enhanced Chemical Vapor Deposition) process which produces less plasma-induced damage than the conventional PECVD. Through the optical and electrical measurements of the deposited films, we optimized the various RPECVD process parameters. The optimized silicon nitride films showed excellent characteristics such as small etch rate (approx 33 A/min by 7:1 BHF), high breakdown field (>9 MV/cm), and low compressive stress (approx 3.3x10 sup 9 dyne/cm sup 2). We successfully applied thin RPECVD silicon nitride films to the surface passivation of GaAs pseudomorphic high electron mobility transistors (P-HEMTs) with negligible degradations in DC and RF characteristics.

  3. Gallium nitride heterostructures on 3D structured silicon.

    Science.gov (United States)

    Fündling, Sönke; Sökmen, Unsal; Peiner, Erwin; Weimann, Thomas; Hinze, Peter; Jahn, Uwe; Trampert, Achim; Riechert, Henning; Bakin, Andrey; Wehmann, Hergo-Heinrich; Waag, Andreas

    2008-10-08

    We investigated GaN-based heterostructures grown on three-dimensionally patterned Si(111) substrates by metal organic vapour phase epitaxy, with the goal of fabricating well controlled high quality, defect reduced GaN-based nanoLEDs. The high aspect ratios of such pillars minimize the influence of the lattice mismatched substrate and improve the material quality. In contrast to other approaches, we employed deep etched silicon substrates to achieve a controlled pillar growth. For that a special low temperature inductively coupled plasma etching process has been developed. InGaN/GaN multi-quantum-well structures have been incorporated into the pillars. We found a pronounced dependence of the morphology of the GaN structures on the size and pitch of the pillars. Spatially resolved optical properties of the structures are analysed by cathodoluminescence.

  4. Gallium nitride heterostructures on 3D structured silicon

    Energy Technology Data Exchange (ETDEWEB)

    Fuendling, Soenke; Soekmen, Uensal; Peiner, Erwin; Bakin, Andrey; Wehmann, Hergo-Heinrich; Waag, Andreas [Institut fuer Halbleitertechnik, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Weimann, Thomas; Hinze, Peter [Physikalisch Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany); Jahn, Uwe; Trampert, Achim; Riechert, Henning [Paul-Drude-Institut fuer Festkoerperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)], E-mail: s.fuendling@tu-bs.de

    2008-10-08

    We investigated GaN-based heterostructures grown on three-dimensionally patterned Si(111) substrates by metal organic vapour phase epitaxy, with the goal of fabricating well controlled high quality, defect reduced GaN-based nanoLEDs. The high aspect ratios of such pillars minimize the influence of the lattice mismatched substrate and improve the material quality. In contrast to other approaches, we employed deep etched silicon substrates to achieve a controlled pillar growth. For that a special low temperature inductively coupled plasma etching process has been developed. InGaN/GaN multi-quantum-well structures have been incorporated into the pillars. We found a pronounced dependence of the morphology of the GaN structures on the size and pitch of the pillars. Spatially resolved optical properties of the structures are analysed by cathodoluminescence.

  5. Strength and fatigue of NT551 silicon nitride and NT551 diesel exhaust valves

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, M.J.; Werezczak, A.A.; Kirkland, T.P.; Breder, K.

    2000-02-01

    The content of this report is excerpted from Mark Andrew's Ph.D. Thesis (Andrews, 1999), which was funded by a DOE/OTT High Temperature Materials Laboratory Graduate Fellowship. It involves the characterization of NT551 and valves fabricated with it. The motivations behind using silicon nitride (Si{sub 3}N{sub 4}) as an exhaust valve for a diesel engine are presented in this section. There are several economic factors that have encouraged the design and implementation of ceramic components for internal combustion (IC) engines. The reasons for selecting the diesel engine valve for this are also presented.

  6. The influence of processing conditions on the microstructure and the mechanical properties of reaction sintered silicon nitride

    International Nuclear Information System (INIS)

    Heinrich, J.

    1979-09-01

    The microstructure of reaction sintered silicon nitride (RBSN) was changed in a wide range of varying green density, grain size of the silicon starting powder, nitriding conditions, and by introducing artificial pores. The influence of single microstructural parameters on mechanical properties like room temperature strength, creep behaviour, and resistance to thermal shock has been investigated. The essential factors influencing these properties were found to be total porosity, pore size distribution, and the fractions of α- and β-Si 3 N 4 . In view of high temperature engineering applications of RBSN possibilities to optimize the material's properties by controlled processing are discussed. (orig.) [de

  7. A SRF niobium cylindrical cavity with a large silicon nitride niobium-coated membrane as one end-wall

    Science.gov (United States)

    Martinez, Luis; Castelli, Alessandro; Pate, Jacob; Thompson, Johnathon; Delmas, William; Sharping, Jay; Chiao, Raymond; Chiao Team; Sharping Team

    The development of large silicon nitride membranes and niobium film deposition techniques motivate new architectures in opto-mechanics and microwave devices that can exploit the extremely high Q's obtainable with superconducting radio frequency (SRF) niobium cavities. We present a X-band SRF cylindrical cavity-membrane system in which one end-wall of the cavity is replaced by a niobium coated centimeter-sized silicon nitride membrane. We report moderately high Q factors above 10 million. Experimental results characterizing the system and potential future applications for such schemes in microwave devices and optomechanics are discussed.

  8. Laser cutting of silicon with the liquid jet guided laser using a chlorine-containing jet media

    Energy Technology Data Exchange (ETDEWEB)

    Hopman, Sybille; Mayer, Kuno; Fell, Andreas; Mesec, Matthias; Granek, Filip [Fraunhofer Institute for Solar Energy Systems ISE, Freiburg (Germany)

    2011-03-15

    In this paper results for liquid media are presented, which are used the first time as liquid jet for cutting of silicon with laser chemical processing (LCP). The liquids contain a perfluoro-carbon compound as solvent and elemental chlorine as etching agent for silicon. Experiments were performed to investigate its influence on groove form and maximum achieved groove depth. It is shown that with the addition of low-concentration chlorine, the groove depth can already be significantly increased. The groove shape could be changed from a V-profile to a U-profile. Furthermore, an about four times greater groove depth was achieved by applying a saturated chlorine solution compared to groove depths without using chlorine. Finally, a theory is given and discussed to describe the phenomena observed. (orig.)

  9. Sub-micron silicon nitride waveguide fabrication using conventional optical lithography.

    Science.gov (United States)

    Huang, Yuewang; Zhao, Qiancheng; Kamyab, Lobna; Rostami, Ali; Capolino, Filippo; Boyraz, Ozdal

    2015-03-09

    We demonstrate a novel technique to fabricate sub-micron silicon nitride waveguides using conventional contact lithography with MEMS-grade photomasks. Potassium hydroxide anisotropic etching of silicon facilitates line reduction and roughness smoothing and is key to the technique. The fabricated waveguides is measured to have a propagation loss of 0.8dB/cm and nonlinear coefficient of γ = 0.3/W/m. A low anomalous dispersion of <100ps/nm/km is also predicted. This type of waveguide is highly suitable for nonlinear optics. The channels naturally formed on top of the waveguide also make it promising for plasmonics and quantum efficiency enhancement in sensing applications.

  10. Deposition of silicon oxynitride films by low energy ion beam assisted nitridation at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Youroukov, S; Kitova, S; Danev, G [Central Laboratory of Photoprocesses, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 109, 113 Sofia (Bulgaria)], E-mail: skitova@clf.bas.bg

    2008-05-01

    The possibility is studied of growing thin silicon oxynitride films by e-gun evaporation of SiO and SiO{sub 2} together with concurrent bombardment with low energy N{sub 2}{sup +} ions from a cyclotron resonance (ECR) source at room temperature of substrates. The degree of nitridation and oxidation of the films is investigated by means of X-ray spectroscopy. The optical characteristics of the films, their environmental stability and adhesion to different substrates are examined. The results obtained show than the films deposited are transparent. It is found that in the case of SiO evaporation with concurrent N{sub 2}{sup +} ion bombardment, reactive implantation of nitrogen within the films takes place at room temperature of the substrate with the formation of a new silicon oxynitride compound even at low ion energy (150-200 eV)

  11. Deposition of silicon oxynitride films by low energy ion beam assisted nitridation at room temperature

    Science.gov (United States)

    Youroukov, S.; Kitova, S.; Danev, G.

    2008-05-01

    The possibility is studied of growing thin silicon oxynitride films by e-gun evaporation of SiO and SiO2 together with concurrent bombardment with low energy N2+ ions from a cyclotron resonance (ECR) source at room temperature of substrates. The degree of nitridation and oxidation of the films is investigated by means of X-ray spectroscopy. The optical characteristics of the films, their environmental stability and adhesion to different substrates are examined. The results obtained show than the films deposited are transparent. It is found that in the case of SiO evaporation with concurrent N2+ ion bombardment, reactive implantation of nitrogen within the films takes place at room temperature of the substrate with the formation of a new silicon oxynitride compound even at low ion energy (150-200 eV).

  12. Determination of impurities in silicon nitride by particle induced x-ray emission analysis

    International Nuclear Information System (INIS)

    Miyagawa, Yoshiko; Saito, Kazuo; Niwa, Hiroaki; Ishizuka, Toshio; Miyagawa, Soji

    1985-01-01

    A method is presented for quantitative particle induced X-ray emission (PIXE) analysis of impurities in the thick samples of silicon nitride. In the analysis of ceramic materials such as silicon nitride, chemical treatments are required to prepare thin enough samples. However, the chemical treatments are undesirable for the PIXE analysis, because another complications are brought about. Our method does not need any chemical treatments and thick samples can be subjected to the measurements. The determination of impurities were made by on-line use of a personal computer in which standard X-ray intensity data were stored. The method and procedures are as follows: After subtracting a buckground spectrum from an observed PIXE spectrum, the resultant peaks are assigned to individual elements. Then, in order to determine the contents of the impurities, the intensity of each peak is compared with a Gaussian curve which is generated from the standard X-ray intensity data. The latter data were determined theoretically. The results were in satisfactory agreement with those obtained by ICP emission spectrometry. (author)

  13. Effect of Silicon Nitride Balls and Rollers on Rolling Bearing Life

    Science.gov (United States)

    Zaretsky, Erwin V.; Vlcek, Brian L.; Hendricks, Robert C.

    2005-01-01

    Three decades have passed since the introduction of silicon nitride rollers and balls into conventional rolling-element bearings. For a given applied load, the contact (Hertz) stress in a hybrid bearing will be higher than an all-steel rolling-element bearing. The silicon nitride rolling-element life as well as the lives of the steel races were used to determine the resultant bearing life of both hybrid and all-steel bearings. Life factors were determined and reported for hybrid bearings. Under nominal operating speeds, the resultant calculated lives of the deep-groove, angular-contact, and cylindrical roller hybrid bearings with races made of post-1960 bearing steel increased by factors of 3.7, 3.2, and 5.5, respectively, from those calculated using the Lundberg-Palmgren equations. An all-steel bearing under the same load will have a longer life than the equivalent hybrid bearing under the same conditions. Under these conditions, hybrid bearings are predicted to have a lower fatigue life than all-steel bearings by 58 percent for deep-groove bearings, 41 percent for angular-contact bearings, and 28 percent for cylindrical roller bearings.

  14. Effect of Projectile Materials on Foreign Object Damage of a Gas-Turbine Grade Silicon Nitride

    Science.gov (United States)

    Choi, Sung R.; Racz, Zsolt; Bhatt, Ramakrishna T.; Brewer, David N.; Gyekenyesi, John P.

    2005-01-01

    Foreign object damage (FOD) behavior of AS800 silicon nitride was determined using four different projectile materials at ambient temperature. The target test specimens rigidly supported were impacted at their centers by spherical projectiles with a diameter of 1.59 mm. Four different types of projectiles were used including hardened steel balls, annealed steel balls, silicon nitride balls, and brass balls. Post-impact strength of each target specimen impacted was determined as a function of impact velocity to better understand the severity of local impact damage. The critical impact velocity where target specimens fail upon impact was highest with brass balls, lowest with ceramic ball, and intermediate with annealed and hardened steel balls. Degree of strength degradation upon impact followed the same order as in the critical impact velocity with respect to projectile materials. For steel balls, hardened projectiles yielded more significant impact damage than annealed counterparts. The most important material parameter affecting FOD was identified as hardness of projectiles and was correlated in terms of critical impact velocity, impact deformation, and impact load.

  15. Phosphorus-doped Amorphous Silicon Nitride Films Applied to Crystalline Silicon Solar Cells

    NARCIS (Netherlands)

    Feinäugle, Matthias

    2008-01-01

    The Photovoltaics Group at the Universitat Politècnica de Catalunya is investigating silicon carbide (SiC) for the electronic passivation of the surface of crystalline silicon solar cells. The doping of SiC passivation layers with phosphorus resulted in a clear improvement of the minority carrier

  16. Evaluation of silicon nitride as a substrate for culture of PC12 cells: an interfacial model for functional studies in neurons.

    Directory of Open Access Journals (Sweden)

    Johan Jaime Medina Benavente

    Full Text Available Silicon nitride is a biocompatible material that is currently used as an interfacial surface between cells and large-scale integration devices incorporating ion-sensitive field-effect transistor technology. Here, we investigated whether a poly-L-lysine coated silicon nitride surface is suitable for the culture of PC12 cells, which are widely used as a model for neural differentiation, and we characterized their interaction based on cell behavior when seeded on the tested material. The coated surface was first examined in terms of wettability and topography using contact angle measurements and atomic force microscopy and then, conditioned silicon nitride surface was used as the substrate for the study of PC12 cell culture properties. We found that coating silicon nitride with poly-L-lysine increased surface hydrophilicity and that exposing this coated surface to an extracellular aqueous environment gradually decreased its roughness. When PC12 cells were cultured on a coated silicon nitride surface, adhesion and spreading were facilitated, and the cells showed enhanced morphological differentiation compared to those cultured on a plastic culture dish. A bromodeoxyuridine assay demonstrated that, on the coated silicon nitride surface, higher proportions of cells left the cell cycle, remained in a quiescent state and had longer survival times. Therefore, our study of the interaction of the silicon nitride surface with PC12 cells provides important information for the production of devices that need to have optimal cell culture-supporting properties in order to be used in the study of neuronal functions.

  17. Leachability of nitrided ilmenite in hydrochloric acid

    CSIR Research Space (South Africa)

    Swanepoel, JJ

    2010-10-01

    Full Text Available Titanium nitride in upgraded nitrided ilmenite (bulk of iron removed) can selectively be chlorinated to produce titanium tetrachloride. Except for iron, most other components present during this low temperature (ca. 200 °C) chlorination reaction...

  18. Surface wet-ability modification of thin PECVD silicon nitride layers by 40 keV argon ion treatments

    Science.gov (United States)

    Caridi, F.; Picciotto, A.; Vanzetti, L.; Iacob, E.; Scolaro, C.

    2015-10-01

    Measurements of wet-ability of liquid drops have been performed on a 30 nm silicon nitride (Si3N4) film deposited by a PECVD reactor on a silicon wafer and implanted by 40 keV argon ions at different doses. Surface treatments by using Ar ion beams have been employed to modify the wet-ability. The chemical composition of the first Si3N4 monolayer was investigated by means of X-ray Photoelectron Spectroscopy (XPS). The surface morphology was tested by Atomic Force Microscopy (AFM). Results put in evidence the best implantation conditions for silicon nitride to increase or to reduce the wet-ability of the biological liquid. This permits to improve the biocompatibility and functionality of Si3N4. In particular experimental results show that argon ion bombardment increases the contact angle, enhances the oxygen content and increases the surface roughness.

  19. High performance SONOS flash memory with in-situ silicon nanocrystals embedded in silicon nitride charge trapping layer

    Science.gov (United States)

    Lim, Jae-Gab; Yang, Seung-Dong; Yun, Ho-Jin; Jung, Jun-Kyo; Park, Jung-Hyun; Lim, Chan; Cho, Gyu-seok; Park, Seong-gye; Huh, Chul; Lee, Hi-Deok; Lee, Ga-Won

    2018-02-01

    In this paper, SONOS-type flash memory device with highly improved charge-trapping efficiency is suggested by using silicon nanocrystals (Si-NCs) embedded in silicon nitride (SiNX) charge trapping layer. The Si-NCs were in-situ grown by PECVD without additional post annealing process. The fabricated device shows high program/erase speed and retention property which is suitable for multi-level cell (MLC) application. Excellent performance and reliability for MLC are demonstrated with large memory window of ∼8.5 V and superior retention characteristics of 7% charge loss for 10 years. High resolution transmission electron microscopy image confirms the Si-NC formation and the size is around 1-2 nm which can be verified again in X-ray photoelectron spectroscopy (XPS) where pure Si bonds increase. Besides, XPS analysis implies that more nitrogen atoms make stable bonds at the regular lattice point. Photoluminescence spectra results also illustrate that Si-NCs formation in SiNx is an effective method to form deep trap states.

  20. Steel bonded dense silicon nitride compositions and method for their fabrication

    Science.gov (United States)

    Landingham, Richard L.; Shell, Thomas E.

    1987-01-01

    A two-stage bonding technique for bonding high density silicon nitride and other ceramic materials to stainless steel and other hard metals, and multilayered ceramic-metal composites prepared by the technique are disclosed. The technique involves initially slurry coating a surface of the ceramic material at about 1500.degree. C. in a vacuum with a refractory material and the stainless steel is then pressure bonded to the metallic coated surface by brazing it with nickel-copper-silver or nickel-copper-manganese alloys at a temperature in the range of about 850.degree. to 950.degree. C. in a vacuum. The two-stage bonding technique minimizes the temperature-expansion mismatch between the dissimilar materials.

  1. Observation of ultraslow stress release in silicon nitride films on CaF2

    International Nuclear Information System (INIS)

    Guo, Tianyi; Deen, M. Jamal; Xu, Changqing; Fang, Qiyin; Selvaganapathy, P. Ravi; Zhang, Haiying

    2015-01-01

    Silicon nitride thin films are deposited by plasma-enhanced chemical vapor deposition on (100) and (111) CaF 2 crystalline substrates. Delaminated wavy buckles formed during the release of internal compressive stress in the films and the stress releasing processes are observed macroscopically and microscopically. The stress release patterns start from the substrate edges and propagate to the center along defined directions aligned with the crystallographic orientations of the substrate. The stress releasing velocity of SiN x film on (111) CaF 2 is larger than that of SiN x film with the same thickness on (100) CaF 2 . The velocities of SiN x film on both (100) and (111) CaF 2 increase with the film thickness. The stress releasing process is initiated when the films are exposed to atmosphere, but it is not a chemical change from x-ray photoelectron spectroscopy

  2. MgB2 thin films on silicon nitride substrates prepared by an in situ method

    International Nuclear Information System (INIS)

    Monticone, Eugenio; Gandini, Claudio; Portesi, Chiara; Rajteri, Mauro; Bodoardo, Silvia; Penazzi, Nerino; Dellarocca, Valeria; Gonnelli, Renato S

    2004-01-01

    Large-area MgB 2 thin films were deposited on silicon nitride and sapphire substrates by co-deposition of Mg and B. After a post-annealing in Ar atmosphere at temperatures between 773 and 1173 K depending on the substrate, the films showed a critical temperature higher than 35 K with a transition width less than 0.5 K. The x-ray diffraction pattern suggested a c-axis preferential orientation in films deposited on amorphous substrate. The smooth surface and the good structural properties of these MgB 2 films allowed their reproducible patterning by a standard photolithographic process down to dimensions of the order of 10 μm and without a considerable degradation of the superconducting properties

  3. Observation of ultraslow stress release in silicon nitride films on CaF{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Tianyi [School of Biomedical Engineering, McMaster University, 1280 Main St W, Hamilton, Ontario L8S 4K1, Canada and Institute of Microelectronics, Chinese Academy of Science, Beijing 100029 (China); Deen, M. Jamal, E-mail: jamal@mcmaster.ca [Department of Electrical and Computer Engineering, McMaster University, 1280 Main St W, Hamilton, Ontario L8S 4K1, Canada and School of Biomedical Engineering, McMaster University, 1280 Main St W, Hamilton, Ontario L8S 4K1 (Canada); Xu, Changqing; Fang, Qiyin [Department of Engineering Physics, McMaster University, 1280 Main St W, Hamilton, Ontario L8S 4L7 (Canada); Selvaganapathy, P. Ravi [Department of Mechanical Engineering, McMaster University, 1280 Main St W, Hamilton, Ontario L8S 4L7 (Canada); Zhang, Haiying [Institute of Microelectronics, Chinese Academy of Science, Beijing 100029 (China)

    2015-07-15

    Silicon nitride thin films are deposited by plasma-enhanced chemical vapor deposition on (100) and (111) CaF{sub 2} crystalline substrates. Delaminated wavy buckles formed during the release of internal compressive stress in the films and the stress releasing processes are observed macroscopically and microscopically. The stress release patterns start from the substrate edges and propagate to the center along defined directions aligned with the crystallographic orientations of the substrate. The stress releasing velocity of SiN{sub x} film on (111) CaF{sub 2} is larger than that of SiN{sub x} film with the same thickness on (100) CaF{sub 2}. The velocities of SiN{sub x} film on both (100) and (111) CaF{sub 2} increase with the film thickness. The stress releasing process is initiated when the films are exposed to atmosphere, but it is not a chemical change from x-ray photoelectron spectroscopy.

  4. Young's modulus and fracture toughness of silicon nitride ceramics at elevated temperature

    Energy Technology Data Exchange (ETDEWEB)

    Rouxel, T. [Rennes Univ. (France). Lab. de Recherche en Mecanique Applicee

    2002-07-01

    The temperature dependencies of Young's modulus (E) and fracture toughness (K{sub 1c}) of several silicon nitride-based monolithic and composite materials, are reviewed. A transition range is observed between 1130 and 1180 C on the E(T) curves, which is systematically 150 to 200 C above the T{sub g} of oxynitride glasses of composition close to that of the intergranular glassy pockets. It is thus supposed that this transition reflects the behaviour of the interfacial glassy films. The higher the glassy phase content, the higher is the temperature sensitivity. The presence of SiC particles greatly attenuates the sensitivity. Thus, Young's modulus decreases more slowly with temperature and fracture toughness changes little up to 1300 C. The K{sub 1c} (T) curves exhibit four different stages which are discussed and interpreted on the basis of a theoretical model. (orig.)

  5. Dependence of wet etch rate on deposition, annealing conditions and etchants for PECVD silicon nitride film

    International Nuclear Information System (INIS)

    Tang Longjuan; Zhu Yinfang; Yang Jinling; Li Yan; Zhou Wei; Xie Jing; Liu Yunfei; Yang Fuhua

    2009-01-01

    The influence of deposition, annealing conditions, and etchants on the wet etch rate of plasma enhanced chemical vapor deposition (PECVD) silicon nitride thin film is studied. The deposition source gas flow rate and annealing temperature were varied to decrease the etch rate of SiN x :H by HF solution. A low etch rate was achieved by increasing the SiH 4 gas flow rate or annealing temperature, or decreasing the NH 3 and N2 gas flow rate. Concentrated, buffered, and dilute hydrofluoric acid were utilized as etchants for SiO 2 and SiN x :H. A high etching selectivity of SiO 2 over SiN x :H was obtained using highly concentrated buffered HF.

  6. Characterization of the porosity of silicon nitride thin layers by Electrochemical Impedance Spectroscopy

    International Nuclear Information System (INIS)

    Barrès, T.; Tribollet, B.; Stephan, O.; Montigaud, H.; Boinet, M.; Cohin, Y.

    2017-01-01

    Silicon nitride thin films are widely used as diffusion barriers within stacks in the glass industry but turn out to be porous at the nanometric scale. EIS measurements were conducted on SiNx thin layers deposited on a gold layer. An electrochemical model was established to fit the EIS measurements making use of data from other complementary techniques. In particular, Transmission Electron Microscopy was performed on these thin layers to determine the diameter and the qualitative morphology of the pores. A quantitative determination of the through-porosity of the layer was deduced from the EIS model and was in good agreement with TEM measurements. Moreover, combining EIS with local observations enabled inhomogeneities in the layer to be probed by highlighting a specific region in the layer.

  7. Low-loss compact multilayer silicon nitride platform for 3D photonic integrated circuits.

    Science.gov (United States)

    Shang, Kuanping; Pathak, Shibnath; Guan, Binbin; Liu, Guangyao; Yoo, S J B

    2015-08-10

    We design, fabricate, and demonstrate a silicon nitride (Si(3)N(4)) multilayer platform optimized for low-loss and compact multilayer photonic integrated circuits. The designed platform, with 200 nm thick waveguide core and 700 nm interlayer gap, is compatible for active thermal tuning and applicable to realizing compact photonic devices such as arrayed waveguide gratings (AWGs). We achieve ultra-low loss vertical couplers with 0.01 dB coupling loss, multilayer crossing loss of 0.167 dB at 90° crossing angle, 50 μm bending radius, 100 × 2 μm(2) footprint, lateral misalignment tolerance up to 400 nm, and less than -52 dB interlayer crosstalk at 1550 nm wavelength. Based on the designed platform, we demonstrate a 27 × 32 × 2 multilayer star coupler.

  8. Effect of loading rate on dynamic fracture of reaction bonded silicon nitride

    Science.gov (United States)

    Liaw, B. M.; Kobayashi, A. S.; Emery, A. F.

    1986-01-01

    Wedge-loaded, modified tapered double cantilever beam (WL-MTDCB) specimens under impact loading were used to determine the room temperature dynamic fracture response of reaction bonded silicon nitride (RBSN). The crack extension history, with the exception of the terminal phase, was similar to that obtained under static loading. Like its static counterpart, a distinct crack acceleration phase, which was not observed in dynamic fracture of steel and brittle polymers, was noted. Unlike its static counterpart, the crack continued to propagate at nearly its terminal velocity under a low dynamic stress intensity factor during the terminal phase of crack propagation. These and previously obtained results for glass and RBSN show that dynamic crack arrest under a positive dynamic stress intensity factor is unlikely in static and impact loaded structural ceramics.

  9. Pressure bonding molybdenum alloy (TZM) to reaction-bonded silicon nitride

    International Nuclear Information System (INIS)

    Huffsmith, S.A.; Landingham, R.L.

    1978-01-01

    Topping cycles could boost the energy efficiencies of a variety of systems by using what is now waste heat. One such topping cycle uses a ceramic helical expander and would require that a reaction-bonded silicon nitride (RBSN) rotor be bonded to a shaft of TZM (Mo-0.5 wt % Ti-0.08 wt % Zr). Coupon studies show that TZM can be bonded to RBSN at 1300 0 C and 69 MPa if there is an interlayer of MoSi 2 . A layer of finely ground (10 μm) MoSi 2 facilitates bond formation and provides a thicker bond interface. The hardness and grain structure of the TZM and RBSN were not affected by the temperature and pressure required to bond the coupons

  10. Single Photon Counting UV Solar-Blind Detectors Using Silicon and III-Nitride Materials

    Science.gov (United States)

    Nikzad, Shouleh; Hoenk, Michael; Jewell, April D.; Hennessy, John J.; Carver, Alexander G.; Jones, Todd J.; Goodsall, Timothy M.; Hamden, Erika T.; Suvarna, Puneet; Bulmer, J.; Shahedipour-Sandvik, F.; Charbon, Edoardo; Padmanabhan, Preethi; Hancock, Bruce; Bell, L. Douglas

    2016-01-01

    Ultraviolet (UV) studies in astronomy, cosmology, planetary studies, biological and medical applications often require precision detection of faint objects and in many cases require photon-counting detection. We present an overview of two approaches for achieving photon counting in the UV. The first approach involves UV enhancement of photon-counting silicon detectors, including electron multiplying charge-coupled devices and avalanche photodiodes. The approach used here employs molecular beam epitaxy for delta doping and superlattice doping for surface passivation and high UV quantum efficiency. Additional UV enhancements include antireflection (AR) and solar-blind UV bandpass coatings prepared by atomic layer deposition. Quantum efficiency (QE) measurements show QE > 50% in the 100–300 nm range for detectors with simple AR coatings, and QE ≅ 80% at ~206 nm has been shown when more complex AR coatings are used. The second approach is based on avalanche photodiodes in III-nitride materials with high QE and intrinsic solar blindness. PMID:27338399

  11. Deuterated silicon nitride photonic devices for broadband optical frequency comb generation

    Science.gov (United States)

    Chiles, Jeff; Nader, Nima; Hickstein, Daniel D.; Yu, Su Peng; Briles, Travis Crain; Carlson, David; Jung, Hojoong; Shainline, Jeffrey M.; Diddams, Scott; Papp, Scott B.; Nam, Sae Woo; Mirin, Richard P.

    2018-04-01

    We report and characterize low-temperature, plasma-deposited deuterated silicon nitride thin films for nonlinear integrated photonics. With a peak processing temperature less than 300$^\\circ$C, it is back-end compatible with pre-processed CMOS substrates. We achieve microresonators with a quality factor of up to $1.6\\times 10^6 $ at 1552 nm, and $>1.2\\times 10^6$ throughout $\\lambda$ = 1510 -- 1600 nm, without annealing or stress management. We then demonstrate the immediate utility of this platform in nonlinear photonics by generating a 1 THz free spectral range, 900-nm-bandwidth modulation-instability microresonator Kerr comb and octave-spanning, supercontinuum-broadened spectra.

  12. Broadband enhancement of single photon emission and polarization dependent coupling in silicon nitride waveguides.

    Science.gov (United States)

    Bisschop, Suzanne; Guille, Antoine; Van Thourhout, Dries; Hens, Zeger; Brainis, Edouard

    2015-06-01

    Single-photon (SP) sources are important for a number of optical quantum information processing applications. We study the possibility to integrate triggered solid-state SP emitters directly on a photonic chip. A major challenge consists in efficiently extracting their emission into a single guided mode. Using 3D finite-difference time-domain simulations, we investigate the SP emission from dipole-like nanometer-sized inclusions embedded into different silicon nitride (SiNx) photonic nanowire waveguide designs. We elucidate the effect of the geometry on the emission lifetime and the polarization of the emitted SP. The results show that highly efficient and polarized SP sources can be realized using suspended SiNx slot-waveguides. Combining this with the well-established CMOS-compatible processing technology, fully integrated and complex optical circuits for quantum optics experiments can be developed.

  13. Direct bonding of ALD Al2O3 to silicon nitride thin films

    DEFF Research Database (Denmark)

    Laganà, Simone; Mikkelsen, E. K.; Marie, Rodolphe

    2017-01-01

    microscopy (TEM) by improving low temperature annealing bonding strength when using atomic layer deposition of aluminum oxide. We have investigated and characterized bonding of Al2O3-SixNy (low stress silicon rich nitride) and Al2O3-Si3N4 (stoichiometric nitride) thin films annealed from room temperature up......O3 can be bonded to. Preliminary tests demonstrating a well-defined nanochannel system with-100 nm high channels successfully bonded and tests against leaks using optical fluorescence technique and transmission electron microscopy (TEM) characterization of liquid samples are also reported. Moreover...

  14. Stressing effects on the charge trapping of silicon oxynitride prepared by thermal oxidation of LPCVD Si-rich silicon nitride

    International Nuclear Information System (INIS)

    Choi, H.Y.; Wong, H.; Filip, V.; Sen, B.; Kok, C.W.; Chan, M.; Poon, M.C.

    2006-01-01

    It was recently found that the silicon oxynitride prepared by oxidation of silicon-rich silicon nitride (SRN) has several important features. The high nitrogen and extremely low hydrogen content of this material allows it to have a high dielectric constant and a low trap density. The present work investigates in further detail the electrical reliability of this kind of gate dielectric films by studying the charge trapping and interface state generation induced by constant current stressing. Capacitance-voltage (C-V) measurements indicate that for oxidation temperatures of 850 and 950 deg. C, the interface trap generation is minimal because of the high nitrogen content at the interface. At a higher oxidation temperature of 1050 deg. C, a large flatband shift is found for constant current stressing. This observation can be explained by the significant reduction of the nitrogen content and the phase separation effect at this temperature as found by X-ray photoelectron spectroscopy study. In addition to the high nitrogen content, the Si atoms at the interface exist in the form of random bonding to oxygen and nitrogen atoms for samples oxidized at 850 and 950 deg. C. This structure reduces the interface bonding constraint and results in the low interface trap density. For heavily oxidized samples the trace amount of interface nitrogen atoms exist in the form of a highly constraint SiN 4 phase and the interface oxynitride layer is a random mixture of SiO 4 and SiN 4 phases, which consequently reduces the reliability against high energy electron stressing

  15. Final report. Fabrication of silicon carbide/silicon nitride nanocomposite materials and characterization of their performance; Herstellung von Siliciumcarbid/Siliciumnitrid-Nanocomposite-Werkstoffen und Charakterisierung ihrer Leistungsfaehigkeit. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Westerheide, R.; Woetting, G.; Schmitz, H.W.

    1998-07-01

    The presented activities were initiated by the well known publications of Niihara and Ishizaki. There, the strengthening and toughening of silicon nitride by nanoscaled silicon carbide particles are described. Both authors have used expensive powder production routes to achieve the optimum mechanical properties. However, for a commercial purpose these routes are not applicable due to their high cost and low reproducibility. The production route chosen by H.C. Starck together with CFI and the Fraunhofer-Institute is a powder synthesis based on the carbothermal reaction of silicon nitride as a low cost synthesis method. The investigations were performed for materials made from synthesis powders and other reference materials. The materials were densified with relatively high amounts of conventional sintering additives by gas pressure sintering. It is shown, that the postulated maxima of strength and fracture toughness behaviour at room temperature with maxima at about 5% to 25% nanoscaled SiC cannot be achieved. However, the mechanical high temperature material behaviour is as good as the behaviour of highly developed silicon nitride materials, which are produced by HIP or by consequent minimisation of the additive content with the well known difficulties to densify these materials. An overview will be given here on the powder production route and their specific problems, the mechanical properties, the microstructure and the possible effects of the microstructure, which result in an improvement of the creep resistance. (orig.)

  16. Suppression of interfacial voids formation during silane (SiH4)-based silicon oxide bonding with a thin silicon nitride capping layer

    Science.gov (United States)

    Lee, Kwang Hong; Bao, Shuyu; Wang, Yue; Fitzgerald, Eugene A.; Seng Tan, Chuan

    2018-01-01

    The material properties and bonding behavior of silane-based silicon oxide layers deposited by plasma-enhanced chemical vapor deposition were investigated. Fourier transform infrared spectroscopy was employed to determine the chemical composition of the silicon oxide films. The incorporation of hydroxyl (-OH) groups and moisture absorption demonstrates a strong correlation with the storage duration for both as-deposited and annealed silicon oxide films. It is observed that moisture absorption is prevalent in the silane-based silicon oxide film due to its porous nature. The incorporation of -OH groups and moisture absorption in the silicon oxide films increase with the storage time (even in clean-room environments) for both as-deposited and annealed silicon oxide films. Due to silanol condensation and silicon oxidation reactions that take place at the bonding interface and in the bulk silicon, hydrogen (a byproduct of these reactions) is released and diffused towards the bonding interface. The trapped hydrogen forms voids over time. Additionally, the absorbed moisture could evaporate during the post-bond annealing of the bonded wafer pair. As a consequence, defects, such as voids, form at the bonding interface. To address the problem, a thin silicon nitride capping film was deposited on the silicon oxide layer before bonding to serve as a diffusion barrier to prevent moisture absorption and incorporation of -OH groups from the ambient. This process results in defect-free bonded wafers.

  17. Effect of the stoichiometry of Si-rich silicon nitride thin films on their photoluminescence and structural properties

    Energy Technology Data Exchange (ETDEWEB)

    Torchynska, T.V., E-mail: ttorch@esfm.ipn.mx [ESFM—Instituto Politecnico Nacional, Mexico DF 07738 (Mexico); Casas Espinola, J.L. [ESFM—Instituto Politecnico Nacional, Mexico DF 07738 (Mexico); Vergara Hernandez, E. [UPIITA—Instituto Politecnico Nacional, Mexico DF 07320 (Mexico); Khomenkova, L., E-mail: khomen@ukr.net [V. Lashkaryov Institute of Semiconductor Physics, 45 Pr. Nauky, 03028 Kyiv (Ukraine); Delachat, F.; Slaoui, A. [ICube, 23 rue du Loess, BP 20 CR, 67037 Strasbourg Cedex 2 (France)

    2015-04-30

    Si-rich Silicon nitride films were grown on silicon substrates by plasma enhanced chemical vapor deposition. The film stoichiometry was controlled via the variation of NH{sub 3}/SiH{sub 4} ratio from 0.45 up to 1.0. Thermal annealing at 1100 °C for 30 min in the nitrogen flow was applied to form the Si nanocrystals in the films that have been investigated by means of photoluminescence and Raman scattering methods, as well as transmission electron microscopy. Several emission bands have been detected with the peak positions at: 2.8–3.0 eV, 2.5–2.7 eV, 2.10–2.25 eV, and 1.75–1.98 eV. The temperature dependences of photoluminescence spectra were studied with the aim to confirm the types of optical transitions and the nature of light emitting defects in silicon nitride. The former three bands were assigned to the defects in silicon nitride, whereas the last one (1.75–1.98 eV) was attributed to the exciton recombination inside of Si nanocrystals. The photoluminescence mechanism is discussed. - Highlights: • Substoichiometric silicon nitride films were grown by PECVD technique. • The variation of the NH{sub 3}/SiH{sub 4} ratio controls excess Si content in the films. • Both Si nanocrystals and amorphous Si phase were observed in annealed films. • Temperature evolution of carrier recombination via Si nanocrystals and host defects.

  18. Numerical study of self-heating effects of small-size MOSFETs fabricated on silicon-on-aluminum nitride substrate

    International Nuclear Information System (INIS)

    Ding Yanfang; Zhu Ziqiang; Zhu Ming; Lin Chenglu

    2006-01-01

    Compared with bulk-silicon technology, silicon-on-insulator (SOI) technology possesses many advantages but it is inevitable that the buried silicon dioxide layer also thermally insulates the metal-oxide-silicon field-effect transistors (MOSFETs) from the bulk due to the low thermal conductivity. One of the alternative insulator to replace the buried oxide layer is aluminum nitride (MN), which has a thermal conductivity that is about 200 times higher than that of SiO 2 (320 W·m -1 ·K -1 versus 1.4 W·m -1 ·K -l ). To investigate the self-heating effects of small-size MOSFETs fabricated on silicon-on-aluminum nitride (SOAN) substrate, a two-dimensional numerical analysis is performed by using a device simulator called MEDICI run on a Solaris workstation to simulate the electrical characteristics and temperature distribution by comparing with those of bulk and standard SOI MOSFETs. Our study suggests that AIN is a suitable alternative to silicon dioxide as a buried dielectric in SOI and expands the applications of SOI to high temperature conditions. (authors)

  19. Synthesis and corrosion properties of silicon nitride films by ion beam assisted deposition

    Science.gov (United States)

    Baba, K.; Hatada, R.; Emmerich, R.; Enders, B.; Wolf, G. K.

    1995-12-01

    Silicon nitride films SiN x were deposited on 316L austenitic stainless steel substrates by silicon evaporation and simultaneous nitrogen ion irradiation with an acceleration voltage of 2 kV. In order to study the influence of the nitrogen content on changes in stoichiometry, structure, morphology, thermal oxidation behaviour and corrosion behaviour, the atom to ion transport ratio was systematically varied. The changes of binding states and the stoichiometry were evaluated with XPS and AES analysis. A maximum nitrogen content was reached with a {Si}/{N} transport ratio lower than 2. The films are chemically inert when exposed to laboratory atmosphere up to a temperature of more than 1000°C. XRD and SEM measurements show amorphous and featureless films for transport ratios {Si}/{N} from 1 up to 10. The variation of the corrosion behaviour of coated stainless steel substrates in sulphuric acid and hydrochloric acid shows a minimum at medium transport ratios. This goes parallel with changes in porosity and adhesion. Additional investigations showed that titanium implantation as an intermediate step improves the corrosion resistance considerably.

  20. Silicon rich nitride ring resonators for rare - earth doped telecommunications-band amplifiers pumped at the O-band.

    Science.gov (United States)

    Xing, P; Chen, G F R; Zhao, X; Ng, D K T; Tan, M C; Tan, D T H

    2017-08-22

    Ring resonators on silicon rich nitride for potential use as rare-earth doped amplifiers pumped at 1310 nm with amplification at telecommunications-band are designed and characterized. The ring resonators are fabricated on 300 nm and 400 nm silicon rich nitride films and characterized at both 1310 nm and 1550 nm. We demonstrate ring resonators exhibiting similar quality factors exceeding 10,000 simultaneously at 1310 nm and 1550 nm. A Dysprosium-Erbium material system exhibiting photoluminescence at 1510 nm when pumped at 1310 nm is experimentally demonstrated. When used together with Dy-Er co-doped particles, these resonators with similar quality factors at 1310 nm and 1550 nm may be used for O-band pumped amplifiers for the telecommunications-band.

  1. WEAR PERFORMANCE OPTIMIZATION OF SILICON NITRIDE USING GENETIC AND SIMULATED ANNEALING ALGORITHM

    Directory of Open Access Journals (Sweden)

    SACHIN GHALME

    2017-12-01

    Full Text Available Replacing damaged joint with the suitable alternative material is a prime requirement in a patient who has arthritis. Generation of wear particles in the artificial joint during action or movement is a serious issue and leads to aseptic loosening of joint. Research in the field of bio-tribology is trying to evaluate materials with minimum wear volume loss so as to extend joint life. Silicon nitride (Si3N4 is non-oxide ceramic suggested as a new alternative for hip/knee joint replacement. Hexagonal Boron Nitride (hBN is recommended as a solid additive lubricant to improve the wear performance of Si3N4 . In this paper, an attempt has been made to evaluate the optimum combination of load and % volume of hBN in Si3N4 to minimize wear volume loss (WVL. The experiments were conducted according to Design of Experiments (DoE – Taguchi method and a mathematical model is developed. Further, this model is processed with Genetic Algorithm (GA and Simulated Annealing (SA to find out the optimum percentage of hBN in Si3N4 to minimize wear volume loss against Alumina (Al2O3 counterface. Taguchi method presents 15 N load and 8% volume of hBN to minimize WVL of Si3N4 . While GA and SA optimization offer 11.08 N load, 12.115% volume of hBN and 11.0789 N load, 12.128% volume of hBN respectively to minimize WVL in Si3N4. .

  2. On-chip photonic microsystem for optical signal processing based on silicon and silicon nitride platforms

    Science.gov (United States)

    Li, Yu; Li, Jiachen; Yu, Hongchen; Yu, Hai; Chen, Hongwei; Yang, Sigang; Chen, Minghua

    2018-04-01

    The explosive growth of data centers, cloud computing and various smart devices is limited by the current state of microelectronics, both in terms of speed and heat generation. Benefiting from the large bandwidth, promising low power consumption and passive calculation capability, experts believe that the integrated photonics-based signal processing and transmission technologies can break the bottleneck of microelectronics technology. In recent years, integrated photonics has become increasingly reliable and access to the advanced fabrication process has been offered by various foundries. In this paper, we review our recent works on the integrated optical signal processing system. We study three different kinds of on-chip signal processors and use these devices to build microsystems for the fields of microwave photonics, optical communications and spectrum sensing. The microwave photonics front receiver was demonstrated with a signal processing range of a full-band (L-band to W-band). A fully integrated microwave photonics transceiver without the on-chip laser was realized on silicon photonics covering the signal frequency of up 10 GHz. An all-optical orthogonal frequency division multiplexing (OFDM) de-multiplier was also demonstrated and used for an OFDM communication system with the rate of 64 Gbps. Finally, we show our work on the monolithic integrated spectrometer with a high resolution of about 20 pm at the central wavelength of 1550 nm. These proposed on-chip signal processing systems potential applications in the fields of radar, 5G wireless communication, wearable devices and optical access networks.

  3. Leachability of nitrided ilmenite in hydrochloric acid

    OpenAIRE

    Swanepoel, J.J.; van Vuuren, D.S.; Heydenrych, M.

    2011-01-01

    Titanium nitride in upgraded nitrided ilmenite (bulk of iron removed) can selectively be chlorinated to produce titanium tetrachloride. Except for iron, most other components present during this low temperature (ca. 200°C) chlorination reaction will not react with chlorine. It is therefore necessary to remove as much iron as possible from the nitrided ilmenite. Hydrochloric acid leaching is a possible process route to remove metallic iron from nitrided ilmenite without excessive dissolution o...

  4. Joining and Integration of Silicon Nitride Ceramics for Aerospace and Energy Systems

    Science.gov (United States)

    Singh, M.; Asthana, R.

    2009-01-01

    Light-weight, creep-resistant silicon nitride ceramics possess excellent high-temperature strength and are projected to significantly raise engine efficiency and performance when used as turbine components in the next-generation turbo-shaft engines without the extensive cooling that is needed for metallic parts. One key aspect of Si3N4 utilization in such applications is its joining response to diverse materials. In an ongoing research program, the joining and integration of Si3N4 ceramics with metallic, ceramic, and composite materials using braze interlayers with the liquidus temperature in the range 750-1240C is being explored. In this paper, the self-joining behavior of Kyocera Si3N4 and St. Gobain Si3N4 using a ductile Cu-based active braze (Cu-ABA) containing Ti will be presented. Joint microstructure, composition, hardness, and strength as revealed by optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Knoop microhardness test, and offset compression shear test will be presented. Additionally, microstructure, composition, and joint strength of Si3N4/Inconel 625 joints made using Cu-ABA, will be presented. The results will be discussed with reference to the role of chemical reactions, wetting behavior, and residual stresses in joints.

  5. Modification of silicon nitride surfaces with GOPES and APTES for antibody immobilization: computational and experimental studies

    International Nuclear Information System (INIS)

    To, Thien Dien; Nguyen, Anh Tuan; Phan, Khoa Nhat Thanh; Truong, An Thu Thi; Doan, Tin Chanh Duc; Dang, Chien Mau

    2015-01-01

    Chemical modification of silicon nitride (SiN) surfaces by silanization has been widely studied especially with 3-(aminopropyl)triethoxysilane (APTES) and 3-(glycidyloxypropyl) dimethylethoxysilane (GOPES). However few reports performed the experimental and computational studies together. In this study, surface modification of SiN surfaces with GOPES and APTES covalently bound with glutaraldehyde (GTA) was investigated for antibody immobilization. The monoclonal anti-cytokeratin-FITC (MACF) antibody was immobilized on the modified SiN surfaces. The modified surfaces were characterized by water contact angle measurements, atomic force microscopy and fluorescence microscopy. The FITC-fluorescent label indicated the existence of MACF antibody on the SiN surfaces and the efficiency of the silanization reaction. Absorption of APTES and GOPES on the oxidized SiN surfaces was computationally modeled and calculated by Materials Studio software. The computational and experimental results showed that modification of the SiN surfaces with APTES and GTA was more effective than the modification with GOPES. (paper)

  6. Fabrication of Silicon Nitride Dental Core Ceramics with Borosilicate Veneering material

    Science.gov (United States)

    Wananuruksawong, R.; Jinawath, S.; Padipatvuthikul, P.; Wasanapiarnpong, T.

    2011-10-01

    Silicon nitride (Si3N4) ceramic is a great candidate for clinical applications due to its high fracture toughness, strength, hardness and bio-inertness. This study has focused on the Si3N4 ceramic as a dental core material. The white Si3N4 was prepared by pressureless sintering at relative low sintering temperature of 1650 °C in nitrogen atmosphere. The coefficient of thermal expansion (CTE) of Si3N4 ceramic is lower than that of Zirconia and Alumina ceramic which are popular in this field. The borosilicate glass veneering was employed due to its compatibility in thermal expansion. The sintered Si3N4 specimens represented the synthetic dental core were paintbrush coated by a veneer paste composed of borosilicate glass powder (tube furnace between 1000-1200°C. The veneered specimens fired at 1100°C for 15 mins show good bonding, smooth and glossy without defect and crazing. The veneer has thermal expansion coefficient as 3.98×10-6 °C-1, rather white and semi opaque, due to zirconia addition, the Vickers hardness as 4.0 GPa which is closely to the human teeth.

  7. Mid-infrared frequency comb via coherent dispersive wave generation in silicon nitride nanophotonic waveguides

    Science.gov (United States)

    Guo, Hairun; Herkommer, Clemens; Billat, Adrien; Grassani, Davide; Zhang, Chuankun; Pfeiffer, Martin H. P.; Weng, Wenle; Brès, Camille-Sophie; Kippenberg, Tobias J.

    2018-06-01

    Mid-infrared optical frequency combs are of significant interest for molecular spectroscopy due to the large absorption of molecular vibrational modes on the one hand, and the ability to implement superior comb-based spectroscopic modalities with increased speed, sensitivity and precision on the other hand. Here, we demonstrate a simple, yet effective, method for the direct generation of mid-infrared optical frequency combs in the region from 2.5 to 4.0 μm (that is, 2,500-4,000 cm-1), covering a large fraction of the functional group region, from a conventional and compact erbium-fibre-based femtosecond laser in the telecommunication band (that is, 1.55 μm). The wavelength conversion is based on dispersive wave generation within the supercontinuum process in an unprecedented large-cross-section silicon nitride (Si3N4) waveguide with the dispersion lithographically engineered. The long-wavelength dispersive wave can perform as a mid-infrared frequency comb, whose coherence is demonstrated via optical heterodyne measurements. Such an approach can be considered as an alternative option to mid-infrared frequency comb generation. Moreover, it has the potential to realize compact dual-comb spectrometers. The generated combs also have a fine teeth-spacing, making them suitable for gas-phase analysis.

  8. The stopping power and energy straggling of heavy ions in silicon nitride and polypropylene

    Energy Technology Data Exchange (ETDEWEB)

    Mikšová, R., E-mail: miksova@ujf.cas.cz [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v. i., 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J. E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Hnatowicz, V. [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v. i., 250 68 Rez (Czech Republic); Macková, A.; Malinský, P. [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v. i., 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J. E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Slepička, P. [Department of Solid State Engineering, Institute of Chemical Technology, 166 28 Prague (Czech Republic)

    2015-07-01

    The stopping power and energy straggling of {sup 12}C{sup 3+} and {sup 16}O{sup 3+} ions with energies between 4.5 and 7.8 MeV in a 0.166-μm-thin silicon nitride and in 4-μm-thin polypropylene foils were measured by means of an indirect transmission method using a half-covered PIPS detector. Ions scattered from a thin gold layer under a scattering angle of 150° were used. The energy spectra of back-scattered and decelerated ions were registered and evaluated simultaneously. The measured stopping powers were compared with the theoretical predictions simulated by SRIM-2008 and MSTAR codes. SRIM prediction of energy stopping is reasonably close to the experimentally obtained values comparing to MSTAR values. Better agreement between experimental and predicted data was observed for C{sup 3+} ion energy losses comparing to O{sup 3+} ions. The experimental data from Paul’s database and our previous experimental data were also discussed. The obtained experimental energy-straggling data were compared to those calculated by using Bohr’s, Yang’s models etc. The predictions by Yang are in good agreement with our experiment within a frame of uncertainty of 25%.

  9. High-Responsivity Graphene-Boron Nitride Photodetector and Autocorrelator in a Silicon Photonic Integrated Circuit.

    Science.gov (United States)

    Shiue, Ren-Jye; Gao, Yuanda; Wang, Yifei; Peng, Cheng; Robertson, Alexander D; Efetov, Dmitri K; Assefa, Solomon; Koppens, Frank H L; Hone, James; Englund, Dirk

    2015-11-11

    Graphene and other two-dimensional (2D) materials have emerged as promising materials for broadband and ultrafast photodetection and optical modulation. These optoelectronic capabilities can augment complementary metal-oxide-semiconductor (CMOS) devices for high-speed and low-power optical interconnects. Here, we demonstrate an on-chip ultrafast photodetector based on a two-dimensional heterostructure consisting of high-quality graphene encapsulated in hexagonal boron nitride. Coupled to the optical mode of a silicon waveguide, this 2D heterostructure-based photodetector exhibits a maximum responsivity of 0.36 A/W and high-speed operation with a 3 dB cutoff at 42 GHz. From photocurrent measurements as a function of the top-gate and source-drain voltages, we conclude that the photoresponse is consistent with hot electron mediated effects. At moderate peak powers above 50 mW, we observe a saturating photocurrent consistent with the mechanisms of electron-phonon supercollision cooling. This nonlinear photoresponse enables optical on-chip autocorrelation measurements with picosecond-scale timing resolution and exceptionally low peak powers.

  10. Atmospheric scanning electron microscope observes cells and tissues in open medium through silicon nitride film.

    Science.gov (United States)

    Nishiyama, Hidetoshi; Suga, Mitsuo; Ogura, Toshihiko; Maruyama, Yuusuke; Koizumi, Mitsuru; Mio, Kazuhiro; Kitamura, Shinichi; Sato, Chikara

    2010-03-01

    Direct observation of subcellular structures and their characterization is essential for understanding their physiological functions. To observe them in open environment, we have developed an inverted scanning electron microscope with a detachable, open-culture dish, capable of 8 nm resolution, and combined with a fluorescence microscope quasi-simultaneously observing the same area from the top. For scanning electron microscopy from the bottom, a silicon nitride film window in the base of the dish maintains a vacuum between electron gun and open sample dish while allowing electrons to pass through. Electrons are backscattered from the sample and captured by a detector under the dish. Cells cultured on the open dish can be externally manipulated under optical microscopy, fixed, and observed using scanning electron microscopy. Once fine structures have been revealed by scanning electron microscopy, their component proteins may be identified by comparison with separately prepared fluorescence-labeled optical microscopic images of the candidate proteins, with their heavy-metal-labeled or stained ASEM images. Furthermore, cell nuclei in a tissue block stained with platinum-blue were successfully observed without thin-sectioning, which suggests the applicability of this inverted scanning electron microscope to cancer diagnosis. This microscope visualizes mesoscopic-scale structures, and is also applicable to non-bioscience fields including polymer chemistry. (c) 2010 Elsevier Inc. All rights reserved.

  11. Identification of light elements in silicon nitride by aberration-corrected scanning transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Idrobo, Juan C., E-mail: idrobojc@ornl.gov [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Walkosz, Weronika [Materials Science Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Department of Physics, University of Illinois at Chicago, Chicago, IL 60607 (United States); Klie, Robert F.; Oeguet, Serdar [Department of Physics, University of Illinois at Chicago, Chicago, IL 60607 (United States)

    2012-12-15

    In silicon nitride structural ceramics, the overall mechanical and thermal properties are controlled by the atomic and electronic structures at the interface between the ceramic grains and the amorphous intergranular films (IGFs) formed by various sintering additives. In the last ten years the atomic arrangements of heavy elements (rare-earths) at the Si{sub 3}N{sub 4}/IGF interfaces have been resolved. However, the atomic position of light elements, without which it is not possible to obtain a complete description of the interfaces, has been lacking. This review article details the authors' efforts to identify the atomic arrangement of light elements such as nitrogen and oxygen at the Si{sub 3}N{sub 4}/SiO{sub 2} interface and in bulk Si{sub 3}N{sub 4} using aberration-corrected scanning transmission electron microscopy. -- Highlights: Black-Right-Pointing-Pointer Revealing the atomic structure of the {alpha}-Si{sub 3}N{sub 4}/SiO{sub 2} interface. Black-Right-Pointing-Pointer Identification and lattice location of oxygen impurities in bulk {alpha}-Si{sub 3}N{sub 4}. Black-Right-Pointing-Pointer Short range ordering of nitrogen and oxygen at the {beta}-Si{sub 3}N{sub 4}/SiO{sub 2} interface.

  12. Fabrication of Silicon Nitride Dental Core Ceramics with Borosilicate Veneering material

    International Nuclear Information System (INIS)

    Wananuruksawong, R; Jinawath, S; Wasanapiarnpong, T; Padipatvuthikul, P

    2011-01-01

    Silicon nitride (Si 3 N 4 ) ceramic is a great candidate for clinical applications due to its high fracture toughness, strength, hardness and bio-inertness. This study has focused on the Si 3 N 4 ceramic as a dental core material. The white Si 3 N 4 was prepared by pressureless sintering at relative low sintering temperature of 1650 deg. C in nitrogen atmosphere. The coefficient of thermal expansion (CTE) of Si 3 N 4 ceramic is lower than that of Zirconia and Alumina ceramic which are popular in this field. The borosilicate glass veneering was employed due to its compatibility in thermal expansion. The sintered Si 3 N 4 specimens represented the synthetic dental core were paintbrush coated by a veneer paste composed of borosilicate glass powder ( 2 O 3 - partial stabilized zirconia) and 30 wt% of polyvinyl alcohol (5 wt% solution). After coating the veneer on the Si 3 N 4 specimens, the firing was performed in electric tube furnace between 1000-1200 deg. C. The veneered specimens fired at 1100 deg. C for 15 mins show good bonding, smooth and glossy without defect and crazing. The veneer has thermal expansion coefficient as 3.98x10 -6 deg. C -1 , rather white and semi opaque, due to zirconia addition, the Vickers hardness as 4.0 GPa which is closely to the human teeth.

  13. EXPERIMENTAL INVESTIGATION ON TRIBOLOGICAL CHARACTERISTICS OF SILICON NITRIDE REINFORCED ALUMINIUM METAL MATRIX COMPOSITES

    Directory of Open Access Journals (Sweden)

    D. BHUVANESH

    2017-05-01

    Full Text Available Aluminium alloy (LM25 reinforced with silicon nitride was fabricated by liquid metallurgy route. The fabricated composite was investigated for dry sliding wear behaviour by conducting experiments using pin-on-disc tribometer. Set of experiments were planned using Taguchi’s technique and data analysis was carried out using L27 orthogonal array. Analysis of Variance (ANOVA technique was used to determine the significance of parameter with respect to wear rate. Signal-to-Noise ratio was employed to detect the most and least influential parameter as well as their level of influence. ‘Smaller the wear’ characteristic was chosen for the analysis of dry sliding wear. Results implied that, the load has the primary effect on the wear succeeded by the effect of sliding velocity and sliding distance. Scanning Electronic Microscopic studies were carried out on worn surfaces to understand the wear mechanism.Tribological results indicated that LM25 aluminium alloy could be better utilized as a material for piston, rotor and bearings for long life in low speed applications.

  14. The stopping power and energy straggling of heavy ions in silicon nitride and polypropylene

    International Nuclear Information System (INIS)

    Mikšová, R.; Hnatowicz, V.; Macková, A.; Malinský, P.; Slepička, P.

    2015-01-01

    The stopping power and energy straggling of 12 C 3+ and 16 O 3+ ions with energies between 4.5 and 7.8 MeV in a 0.166-μm-thin silicon nitride and in 4-μm-thin polypropylene foils were measured by means of an indirect transmission method using a half-covered PIPS detector. Ions scattered from a thin gold layer under a scattering angle of 150° were used. The energy spectra of back-scattered and decelerated ions were registered and evaluated simultaneously. The measured stopping powers were compared with the theoretical predictions simulated by SRIM-2008 and MSTAR codes. SRIM prediction of energy stopping is reasonably close to the experimentally obtained values comparing to MSTAR values. Better agreement between experimental and predicted data was observed for C 3+ ion energy losses comparing to O 3+ ions. The experimental data from Paul’s database and our previous experimental data were also discussed. The obtained experimental energy-straggling data were compared to those calculated by using Bohr’s, Yang’s models etc. The predictions by Yang are in good agreement with our experiment within a frame of uncertainty of 25%

  15. Atomic Layer Deposition of Silicon Nitride from Bis(tert-butylamino)silane and N2 Plasma.

    Science.gov (United States)

    Knoops, Harm C M; Braeken, Eline M J; de Peuter, Koen; Potts, Stephen E; Haukka, Suvi; Pore, Viljami; Kessels, Wilhelmus M M

    2015-09-09

    Atomic layer deposition (ALD) of silicon nitride (SiNx) is deemed essential for a variety of applications in nanoelectronics, such as gate spacer layers in transistors. In this work an ALD process using bis(tert-butylamino)silane (BTBAS) and N2 plasma was developed and studied. The process exhibited a wide temperature window starting from room temperature up to 500 °C. The material properties and wet-etch rates were investigated as a function of plasma exposure time, plasma pressure, and substrate table temperature. Table temperatures of 300-500 °C yielded a high material quality and a composition close to Si3N4 was obtained at 500 °C (N/Si=1.4±0.1, mass density=2.9±0.1 g/cm3, refractive index=1.96±0.03). Low wet-etch rates of ∼1 nm/min were obtained for films deposited at table temperatures of 400 °C and higher, similar to that achieved in the literature using low-pressure chemical vapor deposition of SiNx at >700 °C. For novel applications requiring significantly lower temperatures, the temperature window from room temperature to 200 °C can be a solution, where relatively high material quality was obtained when operating at low plasma pressures or long plasma exposure times.

  16. Structural impact on the eigenenergy renormalization for carbon and silicon allotropes and boron nitride polymorphs

    Science.gov (United States)

    Tutchton, Roxanne; Marchbanks, Christopher; Wu, Zhigang

    2018-05-01

    The phonon-induced renormalization of electronic band structures is investigated through first-principles calculations based on the density functional perturbation theory for nine materials with various crystal symmetries. Our results demonstrate that the magnitude of the zero-point renormalization (ZPR) of the electronic band structure is dependent on both crystal structure and material composition. We have performed analysis of the electron-phonon-coupling-induced renormalization for two silicon (Si) allotropes, three carbon (C) allotropes, and four boron nitride (BN) polymorphs. Phonon dispersions of each material were computed, and our analysis indicates that materials with optical phonons at higher maximum frequencies, such as graphite and hexagonal BN, have larger absolute ZPRs, with the exception of graphene, which has a considerably smaller ZPR despite having phonon frequencies in the same range as graphite. Depending on the structure and material, renormalizations can be comparable to the GW many-body corrections to Kohn-Sham eigenenergies and, thus, need to be considered in electronic structure calculations. The temperature dependence of the renormalizations is also considered, and in all materials, the eigenenergy renormalization at the band gap and around the Fermi level increases with increasing temperature.

  17. Characteristics of laser assisted machining for silicon nitride ceramic according to machining parameters

    International Nuclear Information System (INIS)

    Kim, Jong Do; Lee, Su Jin; Suh, Jeong

    2011-01-01

    This paper describes the Laser Assisted Machining (LAM) that cuts and removes softened parts by locally heating the ceramic with laser. Silicon nitride ceramics can be machined with general machining tools as well, because YSiAlON, which was made up ceramics, is soften at about 1,000 .deg. C. In particular, the laser, which concentrates on highly dense energy, can locally heat materials and very effectively control the temperature of the heated part of specimen. Therefore, this paper intends to propose an efficient machining method of ceramic by deducing the machining governing factors of laser assisted machining and understanding its mechanism. While laser power is the machining factor that controls the temperature, the CBN cutting tool could cut the material more easily as the material gets deteriorated from the temperature increase by increasing the laser power, but excessive oxidation can negatively affect the quality of the material surface after machining. As the feed rate and cutting depth increase, the cutting force increases and tool lifespan decreases, but surface oxidation also decreases. In this experiment, the material can be cut to 3 mm of cutting depth. And based on the results of the experiment, the laser assisted machining mechanism is clarified

  18. Towards a high performing UV-A sensor based on Silicon Carbide and hydrogenated Silicon Nitride absorbing layers

    International Nuclear Information System (INIS)

    Mazzillo, M.; Renna, L.; Costa, N.; Badalà, P.; Sciuto, A.; Mannino, G.

    2016-01-01

    Exposure to ultraviolet (UV) radiation is a major risk factor for most skin cancers. The sun is our primary natural source of UV radiation. The strength of the sun's ultraviolet radiation is expressed as Solar UV Index (UVI). UV-A (320–400 nm) and UV-B (290–320 nm) rays mostly contribute to UVI. UV-B is typically the most destructive form of UV radiation because it has enough energy to cause photochemical damage to cellular DNA. Also overexposure to UV-A rays, although these are less energetic than UV-B photons, has been associated with toughening of the skin, suppression of the immune system, and cataract formation. The use of preventive measures to decrease sunlight UV radiation absorption is fundamental to reduce acute and irreversible health diseases to skin, eyes and immune system. In this perspective UV sensors able to monitor in a monolithic and compact chip the UV Index and relative UV-A and UV-B components of solar spectrum can play a relevant role for prevention, especially in view of the integration of these detectors in close at hand portable devices. Here we present the preliminary results obtained on our UV-A sensor technology based on the use of hydrogenated Silicon Nitride (SiN:H) thin passivating layers deposited on the surface of thin continuous metal film Ni 2 Si/4H-SiC Schottky detectors, already used for UV-Index monitoring. The first UV-A detector prototypes exhibit a very low leakage current density of about 0.2 pA/mm 2 and a peak responsivity value of 0.027 A/W at 330 nm, both measured at 0V bias.

  19. Efficient continuous-wave nonlinear frequency conversion in high-Q gallium nitride photonic crystal cavities on silicon

    Directory of Open Access Journals (Sweden)

    Mohamed Sabry Mohamed

    2017-03-01

    Full Text Available We report on nonlinear frequency conversion from the telecom range via second harmonic generation (SHG and third harmonic generation (THG in suspended gallium nitride slab photonic crystal (PhC cavities on silicon, under continuous-wave resonant excitation. Optimized two-dimensional PhC cavities with augmented far-field coupling have been characterized with quality factors as high as 4.4 × 104, approaching the computed theoretical values. The strong enhancement in light confinement has enabled efficient SHG, achieving a normalized conversion efficiency of 2.4 × 10−3 W−1, as well as simultaneous THG. SHG emission power of up to 0.74 nW has been detected without saturation. The results herein validate the suitability of gallium nitride for integrated nonlinear optical processing.

  20. Effects of Interface Coating and Nitride Enhancing Additive on Properties of Hi-Nicalon SiC Fiber Reinforced Reaction-Bonded Silicon Nitride Composites

    Science.gov (United States)

    Bhatt, Ramakrishana T.; Hull, David R.; Eldridge, Jeffrey I.; Babuder, Raymond

    2000-01-01

    Strong and tough Hi-Nicalon SiC fiber reinforced reaction-bonded silicon nitride matrix composites (SiC/ RBSN) have been fabricated by the fiber lay-up approach. Commercially available uncoated and PBN, PBN/Si-rich PBN, and BN/SiC coated SiC Hi-Nicalon fiber tows were used as reinforcement. The composites contained approximately 24 vol % of aligned 14 micron diameter SiC fibers in a porous RBSN matrix. Both one- and two-dimensional composites were characterized. The effects of interface coating composition, and the nitridation enhancing additive, NiO, on the room temperature physical, tensile, and interfacial shear strength properties of SiC/RBSN matrix composites were evaluated. Results indicate that for all three coated fibers, the thickness of the coatings decreased from the outer periphery to the interior of the tows, and that from 10 to 30 percent of the fibers were not covered with the interface coating. In the uncoated regions, chemical reaction between the NiO additive and the SiC fiber occurs causing degradation of tensile properties of the composites. Among the three interface coating combinations investigated, the BN/SiC coated Hi-Nicalon SiC fiber reinforced RBSN matrix composite showed the least amount of uncoated regions and reasonably uniform interface coating thickness. The matrix cracking stress in SiC/RBSN composites was predicted using a fracture mechanics based crack bridging model.

  1. Galvanic corrosion of structural non-stoichiometric silicon nitride thin films and its implications on reliability of microelectromechanical devices

    Energy Technology Data Exchange (ETDEWEB)

    Broas, M., E-mail: mikael.broas@aalto.fi; Mattila, T. T.; Paulasto-Kröckel, M. [Department of Electrical Engineering and Automation, Aalto University, Espoo, P.O. Box 13500, FIN-00076 Aalto (Finland); Liu, X.; Ge, Y. [Department of Materials Science and Engineering, Aalto University, Espoo, P.O. Box 16200, FIN-00076 Aalto (Finland)

    2015-06-28

    This paper describes a reliability assessment and failure analysis of a poly-Si/non-stoichiometric silicon nitride thin film composite structure. A set of poly-Si/SiN{sub x} thin film structures were exposed to a mixed flowing gas (MFG) environment, which simulates outdoor environments, for 90 days, and an elevated temperature and humidity (85 °C/95% R.H.) test for 140 days. The mechanical integrity of the thin films was observed to degrade during exposure to the chemically reactive atmospheres. The degree of degradation was analyzed with nanoindentation tests. Statistical analysis of the forces required to initiate a fracture in the thin films indicated degradation due to the exposure to the MFG environment in the SiN{sub x} part of the films. Scanning electron microscopy revealed a porous-like reaction layer on top of SiN{sub x}. The morphology of the reaction layer resembled that of galvanically corroded poly-Si. Transmission electron microscopy further clarified the microstructure of the reaction layer which had a complex multi-phase structure extending to depths of ∼100 nm. Furthermore, the layer was oxidized two times deeper in a 90 days MFG-tested sample compared to an untested reference. The formation of the layer is proposed to be caused by galvanic corrosion of elemental silicon in non-stoichiometric silicon nitride during hydrofluoric acid etching. The degradation is proposed to be due uncontrolled oxidation of the films during the stress tests.

  2. Prototype of a silicon nitride ceramic-based miniplate osteofixation system for the midface.

    Science.gov (United States)

    Neumann, Andreas; Unkel, Claus; Werry, Christoph; Herborn, Christoh U; Maier, Horst R; Ragoss, Christian; Jahnke, Klaus

    2006-06-01

    The favorable properties of silicon nitride (Si3N4) ceramics, such as high mean strength level and fracture toughness, suggest biomedical use as an implant material. Minor reservations about the biocompatibility of Si3N4 ceramics were cleared up by previous in vitro and in vivo investigations. A Si3N4 prototype minifixation system was manufactured and implanted for osteosynthesis of artificial frontal bone defects in 3 minipigs. After 3 months, histological sections, computed tomography (CT) scans, and magnetic resonance imaging (MRI) scans were obtained. Finite element modeling (FEM) was used to simulate stresses and strains on Si3N4 miniplates and screws to calculate survival probabilities. Si3N4 miniplates and screws showed satisfying intraoperative workability. There was no implant loss, displacement, or fracture. Bone healing was complete in all animals. The formation of new bone was observed in direct contact to the implants. The implants showed no artifacts on CT and MRI scanning. FEM simulation confirmed the mechanical reliability of the screws, whereas simulated plate geometries regarding pullout forces at maximum load showed limited safety in a bending situation. Si3N4 ceramics show a good biocompatibility outcome both in vitro and in vivo. In ENT surgery, this ceramic may serve as a biomaterial for osteosynthesis (eg, of the midface including reconstruction the floor of the orbit and the skull base). To our knowledge, this is the first introduction of a ceramic-based miniplate-osteofixation system. Advantages compared with titanium are no risk of implantation to bone with mucosal attachment, no need for explantation, and no interference with radiologic imaging. Disadvantages include the impossibility of individual bending of the miniplates.

  3. Performance improvement of silicon nitride ball bearings by ion implantation. CRADA final report

    International Nuclear Information System (INIS)

    Williams, J.M.; Miner, J.

    1998-01-01

    The present report summarizes technical results of CRADA No. ORNL 92-128 with the Pratt and Whitney Division of United Technologies Corporation. The stated purpose of the program was to assess the 3effect of ion implantation on the rolling contact performance of engineering silicon nitride bearings, to determine by post-test analyses of the bearings the reasons for improved or reduced performance and the mechanisms of failure, if applicable, and to relate the overall results to basic property changes including but not limited to swelling, hardness, modulus, micromechanical properties, and surface morphology. Forty-two control samples were tested to an intended runout period of 60 h. It was possible to supply only six balls for ion implantation, but an extended test period goal of 150 h was used. The balls were implanted with C-ions at 150 keV to a fluence of 1.1 x 10 17 /cm 2 . The collection of samples had pre-existing defects called C-cracks in the surfaces. As a result, seven of the control samples had severe spalls before reaching the goal of 60 h for an unacceptable failure rate of 0.003/sample-h. None of the ion-implanted samples experienced engineering failure in 150 h of testing. Analytical techniques have been used to characterize ion implantation results, to characterize wear tracks, and to characterize microstructure and impurity content. In possible relation to C-cracks. It is encouraging that ion implantation can mitigate the C-crack failure mode. However, the practical implications are compromised by the fact that bearings with C-cracks would, in no case, be acceptable in engineering practice, as this type of defect was not anticipated when the program was designed. The most important reason for the use of ceramic bearings is energy efficiency

  4. Fabrication of Silicon Nitride Dental Core Ceramics with Borosilicate Veneering material

    Energy Technology Data Exchange (ETDEWEB)

    Wananuruksawong, R; Jinawath, S; Wasanapiarnpong, T [Research Unit of Advanced Ceramic, Department of Materials Science, Faculty of Science, Chulalongkorn University, Bangkok (Thailand); Padipatvuthikul, P, E-mail: raayaa_chula@hotmail.com [Faculty of Dentistry, Srinakharinwirot University, Bangkok (Thailand)

    2011-10-29

    Silicon nitride (Si{sub 3}N{sub 4}) ceramic is a great candidate for clinical applications due to its high fracture toughness, strength, hardness and bio-inertness. This study has focused on the Si{sub 3}N{sub 4} ceramic as a dental core material. The white Si{sub 3}N{sub 4} was prepared by pressureless sintering at relative low sintering temperature of 1650 deg. C in nitrogen atmosphere. The coefficient of thermal expansion (CTE) of Si{sub 3}N{sub 4} ceramic is lower than that of Zirconia and Alumina ceramic which are popular in this field. The borosilicate glass veneering was employed due to its compatibility in thermal expansion. The sintered Si{sub 3}N{sub 4} specimens represented the synthetic dental core were paintbrush coated by a veneer paste composed of borosilicate glass powder (<150 micrometer, Pyrex) with 5 wt% of zirconia powder (3 wt% Y{sub 2}O{sub 3} - partial stabilized zirconia) and 30 wt% of polyvinyl alcohol (5 wt% solution). After coating the veneer on the Si{sub 3}N{sub 4} specimens, the firing was performed in electric tube furnace between 1000-1200 deg. C. The veneered specimens fired at 1100 deg. C for 15 mins show good bonding, smooth and glossy without defect and crazing. The veneer has thermal expansion coefficient as 3.98x10{sup -6} deg. C{sup -1}, rather white and semi opaque, due to zirconia addition, the Vickers hardness as 4.0 GPa which is closely to the human teeth.

  5. Thermal Response of Cooled Silicon Nitride Plate Due to Thermal Conductivity Effects Analyzed

    Science.gov (United States)

    Baaklini, George Y.; Abdul-Aziz, Ali; Bhatt, Ramakrishna

    2003-01-01

    Lightweight, strong, tough high-temperature materials are required to complement efficiency improvements for next-generation gas turbine engines that can operate with minimum cooling. Because of their low density, high-temperature strength, and high thermal conductivity, ceramics are being investigated as materials to replace the nickelbase superalloys that are currently used for engine hot-section components. Ceramic structures can withstand higher operating temperatures and a harsh combustion environment. In addition, their low densities relative to metals help reduce component mass (ref. 1). To complement the effectiveness of the ceramics and their applicability for turbine engine applications, a parametric study using the finite element method is being carried out. The NASA Glenn Research Center remains very active in conducting and supporting a variety of research activities related to ceramic matrix composites through both experimental and analytical efforts (ref. 1). The objectives of this work are to develop manufacturing technology, develop a thermal and environmental barrier coating (TBC/EBC), develop an analytical modeling capability to predict thermomechanical stresses, and perform a minimal burner rig test on silicon nitride (Si3N4) and SiC/SiC turbine nozzle vanes under simulated engine conditions. Moreover, we intend to generate a detailed database of the material s property characteristics and their effects on structural response. We expect to offer a wide range of data since the modeling will account for other variables, such as cooling channel geometry and spacing. Comprehensive analyses have begun on a plate specimen with Si3N4 cooling holes.

  6. Silicon-Nitride-based Integrated Optofluidic Biochemical Sensors using a Coupled-Resonator Optical Waveguide

    Directory of Open Access Journals (Sweden)

    Jiawei eWANG

    2015-04-01

    Full Text Available Silicon nitride (SiN is a promising material platform for integrating photonic components and microfluidic channels on a chip for label-free, optical biochemical sensing applications in the visible to near-infrared wavelengths. The chip-scale SiN-based optofluidic sensors can be compact due to a relatively high refractive index contrast between SiN and the fluidic medium, and low-cost due to the complementary metal-oxide-semiconductor (CMOS-compatible fabrication process. Here, we demonstrate SiN-based integrated optofluidic biochemical sensors using a coupled-resonator optical waveguide (CROW in the visible wavelengths. The working principle is based on imaging in the far field the out-of-plane elastic-light-scattering patterns of the CROW sensor at a fixed probe wavelength. We correlate the imaged pattern with reference patterns at the CROW eigenstates. Our sensing algorithm maps the correlation coefficients of the imaged pattern with a library of calibrated correlation coefficients to extract a minute change in the cladding refractive index. Given a calibrated CROW, our sensing mechanism in the spatial domain only requires a fixed-wavelength laser in the visible wavelengths as a light source, with the probe wavelength located within the CROW transmission band, and a silicon digital charge-coupled device (CCD / CMOS camera for recording the light scattering patterns. This is in sharp contrast with the conventional optical microcavity-based sensing methods that impose a strict requirement of spectral alignment with a high-quality cavity resonance using a wavelength-tunable laser. Our experimental results using a SiN CROW sensor with eight coupled microrings in the 680nm wavelength reveal a cladding refractive index change of ~1.3 × 10^-4 refractive index unit (RIU, with an average sensitivity of ~281 ± 271 RIU-1 and a noise-equivalent detection limit (NEDL of 1.8 ×10^-8 RIU ~ 1.0 ×10^-4 RIU across the CROW bandwidth of ~1 nm.

  7. Nitride-based Quantum-Confined Structures for Ultraviolet-Visible Optical Devices on Silicon Substrates

    KAUST Repository

    Janjua, Bilal

    2017-04-01

    III–V nitride quantum-confined structures embedded in nanowires (NWs), also known as quantum-disks-in-nanowires (Qdisks-in-NWs), have recently emerged as a new class of nanoscale materials exhibiting outstanding properties for optoelectronic devices and systems. It is promising for circumventing the technology limitation of existing planar epitaxy devices, which are bounded by the lattice-, crystal-structure-, and thermal- matching conditions. This work presents significant advances in the growth of good quality GaN, InGaN and AlGaN Qdisks-in-NWs based on careful optimization of the growth parameters, coupled with a meticulous layer structure and active region design. The NWs were grown, catalyst-free, using plasma assisted molecular beam epitaxy (PAMBE) on silicon (Si) substrates. A 2-step growth scheme was developed to achieve high areal density, dislocation free and vertically aligned NWs on Ti/Si substrates. Numerical modeling of the NWs structures, using the nextnano3 software, showed reduced polarization fields, and, in the presence of Qdisks, exhibited improved quantum-confinement; thus contributing to high carrier radiative-recombination rates. As a result, based on the growth and device structure optimization, the technologically challenging orange and yellow NWs light emitting devices (LEDs) targeting the ‘green-yellow’ gap were demonstrated on scalable, foundry compatible, and low-cost Ti coated Si substrates. The NWs work was also extended to LEDs emitting in the ultraviolet (UV) range with niche applications in environmental cleaning, UV-curing, medicine, and lighting. In this work, we used a Ti (100 nm) interlayer and Qdisks to achieve good quality AlGaN based UV-A (320 - 400 nm) device. To address the issue of UV-absorbing polymer, used in the planarization process, we developed a pendeo-epitaxy technique, for achieving an ultra-thin coalescence of the top p-GaN contact layer, for a self-planarized Qdisks-in-NWs UV-B (280 – 320 nm) LED grown

  8. Influence of hydrogen effusion from hydrogenated silicon nitride layers on the regeneration of boron-oxygen related defects in crystalline silicon

    International Nuclear Information System (INIS)

    Wilking, S.; Ebert, S.; Herguth, A.; Hahn, G.

    2013-01-01

    The degradation effect boron doped and oxygen-rich crystalline silicon materials suffer from under illumination can be neutralized in hydrogenated silicon by the application of a regeneration process consisting of a combination of slightly elevated temperature and carrier injection. In this paper, the influence of variations in short high temperature steps on the kinetics of the regeneration process is investigated. It is found that hotter and longer firing steps allowing an effective hydrogenation from a hydrogen-rich silicon nitride passivation layer result in an acceleration of the regeneration process. Additionally, a fast cool down from high temperature to around 550 °C seems to be crucial for a fast regeneration process. It is suggested that high cooling rates suppress hydrogen effusion from the silicon bulk in a temperature range where the hydrogenated passivation layer cannot release hydrogen in considerable amounts. Thus, the hydrogen content of the silicon bulk after the complete high temperature step can be increased resulting in a faster regeneration process. Hence, the data presented here back up the theory that the regeneration process might be a hydrogen passivation of boron-oxygen related defects

  9. Realization of an ultra-compact polarization beam splitter using asymmetric MMI based on silicon nitride / silicon-on-insulator platform.

    Science.gov (United States)

    Sun, Xiao; Aitchison, J Stewart; Mojahedi, Mo

    2017-04-03

    We have experimentally demonstrated a compact polarization beam splitter (PBS) based on the silicon nitride/silicon-on-insulator platform using the recently proposed augmented-low-index-guiding (ALIG) waveguide structure. The two orthogonal polarizations are split in an asymmetric multimode interference (MMI) section, which was 1.6 μm wide and 4.8 μm long. The device works well over the entire C-band wavelength range and has a measured low insertion loss of less than 1 dB. The polarization extinction ratio at the Bar Port is approximately 17 dB and at the Cross Port is approximately 25 dB. The design of the device is robust and has a good fabrication tolerance.

  10. Influence of post-annealing on the electrical properties of metal/oxide/silicon nitride/oxide/silicon capacitors for flash memories

    International Nuclear Information System (INIS)

    Kim, Hee Dong; An, Ho-Myoung; Kim, Kyoung Chan; Seo, Yu Jeong; Kim, Tae Geun

    2008-01-01

    We report the effect of post-annealing on the electrical properties of metal/oxide/silicon nitride/oxide/silicon (MONOS) capacitors. Four samples, namely as-deposited and annealed at 750, 850 and 950 °C for 30 s in nitrogen ambient by a rapid thermal process, were prepared and characterized for comparison. The best performance with the largest memory window of 4.4 V and the fastest program speed of 10 ms was observed for the sample annealed at 850 °C. In addition, the highest traps density of 6.84 × 10 18 cm −3 was observed with ideal trap distributions for the same sample by capacitance–voltage (C–V) measurement. These results indicate that the memory traps in the ONO structure can be engineered by post-annealing to improve the electrical properties of the MONOS device

  11. Design and fabrication of ultrathin silicon-nitride membranes for use in UV-visible airgap-based MEMS optical filters

    International Nuclear Information System (INIS)

    Ghaderi, Mohammadamir; Wolffenbuttel, Reinoud F.

    2016-01-01

    MEMS-based airgap optical filters are composed of quarter-wave thick high-index dielectric membranes that are separated by airgaps. The main challenge in the fabrication of these filters is the intertwined optical and mechanical requirements. The thickness of the layers decreases with design wavelength, which makes the optical performance in the UV more susceptible to fabrication tolerances, such as thickness and composition of the deposited layers, while the ability to sustain a certain level of residual stress by the structural strength becomes more critical. Silicon-nitride has a comparatively high Young's modulus and good optical properties, which makes it a suitable candidate as the membrane material. However, both the mechanical and optical properties in a silicon-nitride film strongly depend on the specifics of the deposition process. A design trade-off is required between the mechanical strength and the index of refraction, by tuning the silicon content in the silicon-nitride film. However, also the benefit of a high index of refraction in a silicon-rich film should be weighed against the increased UV optical absorption. This work presents the design, fabrication, and preliminary characterization of one and three quarter-wave thick silicon-nitride membranes with a one-quarter airgap and designed to give a spectral reflectance at 400 nm. The PECVD silicon-nitride layers were initially characterized, and the data was used for the optical and mechanical design of the airgap filters. A CMOS compatible process based on polysilicon sacrificial layers was used for the fabrication of the membranes. Optical characterization results are presented. (paper)

  12. Assessments of Mechanical and Life Limiting Properties of Two Candidate Silicon Nitrides for Stirling Convertor Heater Head Applications

    Science.gov (United States)

    Choi, Sung R.; Krause, David L.

    2006-01-01

    NASA Glenn Research Center is developing advanced technology for Stirling convertors with a target of significantly improving the specific power and efficiency of the convertor and overall generator for Mars rovers and deep space missions. One specific approach to the target has been recognized as the use of appropriate high-temperature materials. As a series of ceramic material approaches in Advanced Stirling Convertor Development Program in fiscal year 2005, two commercial, structural silicon nitrides AS800 (Honeywell, Torrence, California) and SN282 (Kyocera, Vancouver, Washington) were selected and their mechanical and life limiting properties were characterized at 1050 C in air. AS800 exhibited both strength and Weibull modulus greater than SN282. A life limiting phenomenon was apparent in AS800 with a low slow crack growth parameter n = 15; whereas, a much increased resistance to slow crack growth was found in SN282 with n greater than 100. Difference in elastic modulus and thermal conductivity was negligible up to 1200 C between the two silicon nitrides. The same was true for the coefficient of thermal expansion up to 1400 C.

  13. Embedded nonvolatile memory devices with various silicon nitride energy band gaps on glass used for flat panel display applications

    International Nuclear Information System (INIS)

    Son, Dang Ngoc; Van Duy, Nguyen; Jung, Sungwook; Yi, Junsin

    2010-01-01

    Nonvolatile memory (NVM) devices with a nitride–nitride–oxynitride stack structure on a rough poly-silicon (poly-Si) surface were fabricated using a low-temperature poly-Si (LTPS) thin film transistor technology on glass substrates for application of flat panel display (FPD). The plasma-assisted oxidation/nitridation method is used to form a uniform oxynitride with an ultrathin tunneling layer on a rough LTPS surface. The NVMs, using a Si-rich silicon nitride film as a charge-trapping layer, were proposed as one of the solutions for the improvement of device performance such as the program/erase speed, the memory window and the charge retention characteristics. To further improve the vertical scaling and charge retention characteristics of NVM devices, the high-κ high-density N-rich SiN x films are used as a blocking layer. The fabricated NVM devices have outstanding electrical properties, such as a low threshold voltage, a high ON/OFF current ratio, a low subthreshold swing, a low operating voltage of less than ±9 V and a large memory window of 3.7 V, which remained about 1.9 V over a period of 10 years. These characteristics are suitable for electrical switching and data storage with in FPD application

  14. Analysis of the properties of silicon nitride based ceramic (Si_3N_4) cutting tool using different addictive

    International Nuclear Information System (INIS)

    Pereira, Joaquim Lopes; Souza, Jose Vitor Candido de; Raymundo, Emerson Augusto; Silva, Oliverio Macedo Moreira

    2013-01-01

    The constant search for new materials is part of the scientific and technological development of the industries. Ceramic been presenting important developments in terms of scientific and technological development, highlighting the predominance of covalent ceramics, which has important applications where abrasion resistance and hardness are required. Between covalent materials, several research papers in search of property improvements and cost reduction. However the production of ceramics of silicon nitride (Si_3N_4) with a reduced cost is possible only if used methods and different additives. The aim of this work is the development of compositions based on silicon nitride (Si_3N_4) using different additives such as Y_2O_3, CeO_2, Al_2O_3 , and CTR_2O_3 in varying amounts. For the development of ceramics, the mixtures were homogenized, dried, compacted and sintered using the sintering process of 1850°C for 1 hour, with a heating rate of 25°C/min. The characterizations were performed as a function of relative density by Archimedes method, the mass loss measured before and after sintering, phase analysis by X-ray diffraction, microstructure by scanning electron microscopy (SEM), and hardness and fracture toughness indentation method. The results showed relative density 97-98, Vickers hardness 17-19 GPa, fracture toughness from 5.6 to 6.8 MPa.m"1"/"2. The different phases were obtained depending on the types of additives used. The obtained results are promising for tribological applications. (author)

  15. Tantalum Nitride Electron-Selective Contact for Crystalline Silicon Solar Cells

    KAUST Repository

    Yang, Xinbo; Aydin, Erkan; Xu, Hang; Kang, Jingxuan; Hedhili, Mohamed N.; Liu, Wenzhu; Wan, Yimao; Peng, Jun; Samundsett, Christian; Cuevas, Andres; De Wolf, Stefaan

    2018-01-01

    novel electron‐selective, passivating contact for c‐Si solar cells is presented. Tantalum nitride (TaN x ) thin films deposited by atomic layer deposition are demonstrated to provide excellent electron‐transporting and hole‐blocking properties

  16. The combined effects of Fe and H2 on the nitridation of silicon

    Science.gov (United States)

    Shaw, N. J.

    1982-01-01

    In view of the support offered by previous work for the suggestion that Fe may affect alpha-Si3N4 formation and microstructural development, a two-part study was conducted to differentiate the effects of H2 and Fe in, first, the nitridation of pure and of Fe-containing powder in N2 and N2-4% H2, and then the nitridation of (1 1 1) Si single crystal wafers with and without Fe powder on the surface. The degree of nitridation is most strongly affected by H2 at 1200 C, but by Fe at 1375 C, where Fe-containing samples in either atmosphere were almost completely nitrided. While neither H2 nor Fe alone changed the ratio of alpha-Si3N4 to beta-Si3N4, the combination of H2 and Fe increased it at both temperatures.

  17. Structure, phonons and related properties in zinc-IV-nitride (IV = silicon, germanium, tin), scandium nitride, and rare-earth nitrides

    Science.gov (United States)

    Paudel, Tula R.

    This thesis presents a study of the phonons and related properties in two sets of nitride compounds, whose properties are until now relatively poorly known. The Zn-IV-N2 group of compounds with the group IV elements Si, Ge and Sn, form a series analogous to the well known III-N nitride series with group III element Al, Ga, In. Structurally, they can be derived by doubling the period of III-V compounds in the plane in two directions and replacing the group-III elements with Zn and a group-IV element in a particular ordered pattern. Even though they are similar to the well-known III-V nitride compounds, the study of the properties of these materials is in its early stages. The phonons in these materials and their relation to the phonons in the corresponding group-III nitrides are of fundamental interest. They are also of practical interest because the phonon related spectra such as infrared absorption and Raman spectroscopy are sensitive to the structural quality of the material and can thus be used to quantify the degree of crystalline perfection of real samples. First-principles calculations of the phonons and related ground state properties of these compounds were carried out using Density Functional Perturbation Theory (DFPT) with the Local Density Approximation (LDA) for exchange and correlation and using a pseudopotential plane wave implementation which was developed by several authors over the last decades. The main focus of our study is on the phonons at the center of the Brillouin zone because the latter are most directly related to commonly used spectroscopies to probe the vibrations in a solid: infrared reflectivity and Raman spectroscopy. For a semiconducting or insulating compound, a splitting occurs between transverse and longitudinal phonons at the Gamma-point because of the long-range nature of electrostatic forces. The concepts required to handle this problem are reviewed. Our discussion emphasizes how the various quantities required are related to

  18. Role of chlorine in the nanocrystalline silicon film formation by rf plasma-enhanced chemical vapor deposition of chlorinated materials

    International Nuclear Information System (INIS)

    Shirai, Hajime

    2004-01-01

    We demonstrate the disorder-induced low-temperature crystallization in the nanocrystalline silicon film growth by rf plasma-enhanced chemical vapor deposition of H 2 -diluted SiH 2 Cl 2 and SiCl 4 . The combination of the chemical reactivity of SiCld (d: dangling bond) and SiHCl complexes and the release of the disorder-induced stress near the growing surface tightly correlate with the phase transitionity of SiCld and SiHCl complexes near the growing surface with the aid of atomic hydrogen, which induce higher degree of disorder in the a-Si network. These features are most prominent in the SiCl 4 compared with those of SiH 2 Cl 2 and SiH 4 , which preferentially enhance the nanocrystalline Si formation

  19. A deep-level transient spectroscopy study of gamma-ray irradiation on the passivation properties of silicon nitride layer on silicon

    Science.gov (United States)

    Dong, Peng; Yu, Xuegong; Ma, Yao; Xie, Meng; Li, Yun; Huang, Chunlai; Li, Mo; Dai, Gang; Zhang, Jian

    2017-08-01

    Plasma-enhanced chemical vapor deposited silicon nitride (SiNx) films are extensively used as passivation material in the solar cell industry. Such SiNx passivation layers are the most sensitive part to gamma-ray irradiation in solar cells. In this work, deep-level transient spectroscopy has been applied to analyse the influence of gamma-ray irradiation on the passivation properties of SiNx layer on silicon. It is shown that the effective carrier lifetime decreases with the irradiation dose. At the same time, the interface state density is significantly increased after irradiation, and its energy distribution is broadened and shifts deeper with respect to the conduction band edge, which makes the interface states becoming more efficient recombination centers for carriers. Besides, C-V characteristics show a progressive negative shift with increasing dose, indicating the generation of effective positive charges in SiNx films. Such positive charges are beneficial for shielding holes from the n-type silicon substrates, i. e. the field-effect passivation. However, based on the reduced carrier lifetime after irradiation, it can be inferred that the irradiation induced interface defects play a dominant role over the trapped positive charges, and therefore lead to the degradation of passivation properties of SiNx on silicon.

  20. Silicon nitride films fabricated by a plasma-enhanced chemical vapor deposition method for coatings of the laser interferometer gravitational wave detector

    Science.gov (United States)

    Pan, Huang-Wei; Kuo, Ling-Chi; Huang, Shu-Yu; Wu, Meng-Yun; Juang, Yu-Hang; Lee, Chia-Wei; Chen, Hsin-Chieh; Wen, Ting Ting; Chao, Shiuh

    2018-01-01

    Silicon is a potential substrate material for the large-areal-size mirrors of the next-generation laser interferometer gravitational wave detector operated in cryogenics. Silicon nitride thin films uniformly deposited by a chemical vapor deposition method on large-size silicon wafers is a common practice in the silicon integrated circuit industry. We used plasma-enhanced chemical vapor deposition to deposit silicon nitride films on silicon and studied the physical properties of the films that are pertinent to application of mirror coatings for laser interferometer gravitational wave detectors. We measured and analyzed the structure, optical properties, stress, Young's modulus, and mechanical loss of the films, at both room and cryogenic temperatures. Optical extinction coefficients of the films were in the 10-5 range at 1550-nm wavelength. Room-temperature mechanical loss of the films varied in the range from low 10-4 to low 10-5 within the frequency range of interest. The existence of a cryogenic mechanical loss peak depended on the composition of the films. We measured the bond concentrations of N - H , Si - H , Si - N , and Si - Si bonds in the films and analyzed the correlations between bond concentrations and cryogenic mechanical losses. We proposed three possible two-level systems associated with the N - H , Si - H , and Si - N bonds in the film. We inferred that the dominant source of the cryogenic mechanical loss for the silicon nitride films is the two-level system of exchanging position between a H+ and electron lone pair associated with the N - H bond. Under our deposition conditions, superior properties in terms of high refractive index with a large adjustable range, low optical absorption, and low mechanical loss were achieved for films with lower nitrogen content and lower N - H bond concentration. Possible pairing of the silicon nitride films with other materials in the quarter-wave stack is discussed.

  1. Dual mechanical behaviour of hydrogen in stressed silicon nitride thin films

    International Nuclear Information System (INIS)

    Volpi, F.; Braccini, M.; Pasturel, A.; Devos, A.; Raymond, G.; Morin, P.

    2014-01-01

    In the present article, we report a study on the mechanical behaviour displayed by hydrogen atoms and pores in silicon nitride (SiN) films. A simple three-phase model is proposed to relate the physical properties (stiffness, film stress, mass density, etc.) of hydrogenated nanoporous SiN thin films to the volume fractions of hydrogen and pores. This model is then applied to experimental data extracted from films deposited by plasma enhanced chemical vapour deposition, where hydrogen content, stress, and mass densities range widely from 11% to 30%, −2.8 to 1.5 GPa, and 2.0 to 2.8 g/cm 3 , respectively. Starting from the conventional plotting of film's Young's modulus against film porosity, we first propose to correct the conventional calculation of porosity volume fraction with the hydrogen content, thus taking into account both hydrogen mass and concentration. The weight of this hydrogen-correction is found to evolve linearly with hydrogen concentration in tensile films (in accordance with a simple “mass correction” of the film density calculation), but a clear discontinuity is observed toward compressive stresses. Then, the effective volume occupied by hydrogen atoms is calculated taking account of the bond type (N-H or Si-H bonds), thus allowing a precise extraction of the hydrogen volume fraction. These calculations applied to tensile films show that both volume fractions of hydrogen and porosity are similar in magnitude and randomly distributed against Young's modulus. However, the expected linear dependence of the Young's modulus is clearly observed when both volume fractions are added. Finally, we show that the stiffer behaviour of compressive films cannot be only explained on the basis of this (hydrogen + porosity) volume fraction. Indeed this stiffness difference relies on a dual mechanical behaviour displayed by hydrogen atoms against the film stress state: while they participate to the stiffness in compressive films, hydrogen atoms mainly

  2. Improving the Microstructure and Electrical Properties of Aluminum Induced Polysilicon Thin Films Using Silicon Nitride Capping Layer

    Directory of Open Access Journals (Sweden)

    Min-Hang Weng

    2014-01-01

    Full Text Available We investigated the capping layer effect of SiNx (silicon nitride on the microstructure, electrical, and optical properties of poly-Si (polycrystalline silicon prepared by aluminum induced crystallization (AIC. The primary multilayer structure comprised Al (30 nm/SiNx (20 nm/a-Si (amorphous silicon layer (100 nm/ITO coated glass and was then annealed in a low annealing temperature of 350°C with different annealing times, 15, 30, 45, and 60 min. The crystallization properties were analyzed and verified by X-ray diffraction (XRD and Raman spectra. The grain growth was analyzed via optical microscope (OM and scanning electron microscopy (SEM. The improved electrical properties such as Hall mobility, resistivity, and dark conductivity were investigated by using Hall and current-voltage (I-V measurements. The results show that the amorphous silicon film has been effectively induced even at a low temperature of 350°C and a short annealing time of 15 min and indicate that the SiNx capping layer can improve the grain growth and reduce the metal content in the induced poly-Si film. It is found that the large grain size is over 20 μm and the carrier mobility values are over 80 cm2/V-s.

  3. Influence of the structural and compositional properties of PECVD silicon nitride layers on the passivation of AIGaN/GaN HEMTs

    NARCIS (Netherlands)

    Karouta, F.; Krämer, M.C.J.C.M.; Kwaspen, J.J.M.; Grzegorczyk, A.; Hageman, P.R.; Hoex, B.; Kessels, W.M.M.; Klootwijk, J.H.; Timmering, E.C.; Smit, M.K.; Wang, J.; Shiojima, K.

    2008-01-01

    We have investigated the influence of the structural and compositional properties of silicon nitride layers on the passivation of AlGaN/GaN HEMTs grown on sapphire substrates by assessing their continuous wave (CW) and pulsed current-voltage (I-V) characteristics. We have looked at the effect of

  4. Effect of pyrolysis atmospheres on the morphology of polymer-derived silicon oxynitrocarbide ceramic films coated aluminum nitride surface and the thermal conductivity of silicone rubber composites

    Science.gov (United States)

    Chiu, Hsien T.; Sukachonmakul, Tanapon; Wang, Chen H.; Wattanakul, Karnthidaporn; Kuo, Ming T.; Wang, Yu H.

    2014-02-01

    Amorphous silicon oxycarbide (SiOC) and silicon oxynitrocarbide (SiONC) ceramic films coated aluminum nitride (AlN) were prepared by using preceramic-polysilazane (PSZ) with dip-coating method, followed by pyrolysis at 700 °C in different (air, Ar, N2 and NH3) atmospheres to converted PSZ into SiOCair and SiONC(Ar,N2andNH3) ceramic. The existence of amorphous SiOCair and SiONC(Ar,N2andNH3) ceramic films on AlN surface was characterized by FTIR, XRD and XPS. The interfacial adhesion between silicone rubber and AlN was significantly improved after the introduction of amorphous SiOCair and SiONC(Ar,N2andNH3) ceramic films on AlN surface. It can be observed from AFM that the pyrolysis of PSZ at different atmosphere strongly affected to films morphology on AlN surface as SiOCair and SiONCNH3 ceramic films were more flat and smooth than SiONCN2 and SiONCAr ceramic films. Besides, the enhancement of the thermal conductivity of silicone rubber composites was found to be related to the decrease in the surface roughness of SiOCair and SiONC(Ar,N2andNH3) ceramic films on AlN surface. This present work provided an alternative surface modification of thermally conductive fillers to improve the thermal conductivity of silicon rubber composites by coating with amorphous SiOCair and SiONC(Ar,N2andNH3) ceramic films.

  5. Surface modification of aluminum nitride by polysilazane and its polymer-derived amorphous silicon oxycarbide ceramic for the enhancement of thermal conductivity in silicone rubber composite

    Science.gov (United States)

    Chiu, Hsien Tang; Sukachonmakul, Tanapon; Kuo, Ming Tai; Wang, Yu Hsiang; Wattanakul, Karnthidaporn

    2014-02-01

    Polysilazane (PSZ) and its polymer-derived amorphous silicon oxycarbide (SiOC) ceramic were coated on aluminum nitride (AlN) by using a dip-coating method to allow moisture-crosslinking of PSZ on AlN, followed by heat treatment at 700 °C in air to convert PSZ into SiOC on AlN. The results from FTIR, XPS and SEM indicated that the surface of AlN was successfully coated by PSZ and SiOC film. It was found that the introduction of PSZ and SiOC film help improve in the interfacial adhesion between the modified AlN (PSZ/AlN and SiOC/AlN) and silicone rubber lead to the increase in the thermal conductivity of the composites since the thermal boundary resistance at the filler-matrix interface was decreased. However, the introduction of SiOC as an intermediate layer between AlN and silicone rubber could help increase the thermal energy transport at the filler-matrix interface rather than using PSZ. This result was due to the decrease in the surface roughness and thickness of SiOC film after heat treatment at 700 °C in air. Thus, in the present work, a SiOC ceramic coating could provide a new surface modification for the improvement of the interfacial adhesion between the thermally conductive filler and the matrix in which can enhance the thermal conductivity of the composites.

  6. The synthesis of a high quality, low cost silicon nitride powder by the carbothermal reduction of silica

    International Nuclear Information System (INIS)

    Cochran, G.A.; Conner, C.L.; Eisman, G.A.; Weimer, A.W.; Carroll, D.F.; Dunmead, S.D.; Hwang, C.J.

    1994-01-01

    The development and emergence of silicon nitride in the marketplace depends on the availability of a high quality, low cost powder which meets or exceeds the requirements for the customer's part application. The Dow Chemical Company, funded by the United States Department of Energy Oak Ridge National Laboratory, is engaged in developing a process which will economically synthesize commercial quantities of such a high quality powder. The Dow Chemical Company's approach is based on the carbothermal reduction of silica and has been shown to produce a sub-micron, equi-axed powder with high alpha content (> 95%), low oxygen (< 2%), and minimal carbon and impurities. This paper will review The Dow Chemical Company program and present preliminary results of the synthesis and powder processing efforts. (orig.)

  7. A Photonic 1 × 4 Power Splitter Based on Multimode Interference in Silicon-Gallium-Nitride Slot Waveguide Structures.

    Science.gov (United States)

    Malka, Dror; Danan, Yossef; Ramon, Yehonatan; Zalevsky, Zeev

    2016-06-25

    In this paper, a design for a 1 × 4 optical power splitter based on the multimode interference (MMI) coupler in a silicon (Si)-gallium nitride (GaN) slot waveguide structure is presented-to our knowledge, for the first time. Si and GaN were found as suitable materials for the slot waveguide structure. Numerical optimizations were carried out on the device parameters using the full vectorial-beam propagation method (FV-BPM). Simulation results show that the proposed device can be useful to divide optical signal energy uniformly in the C-band range (1530-1565 nm) into four output ports with low insertion losses (0.07 dB).

  8. Preparation and characterization of silicon nitride (Si−N)-coated carbon fibers and their effects on thermal properties in composites

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyeon-Hye [R& D Division, Korea Institute of Carbon Convergence Technology, Jeonju 561-844 (Korea, Republic of); Nano& Advanced Materials Engineering, Jeonju University, Jeonju 560-759 (Korea, Republic of); Han, Woong [R& D Division, Korea Institute of Carbon Convergence Technology, Jeonju 561-844 (Korea, Republic of); Lee, Hae-seong [Nano& Advanced Materials Engineering, Jeonju University, Jeonju 560-759 (Korea, Republic of); Min, Byung-Gak [Department of Polymer Science & Engineering, Korea National University of Transportation, Chungju 380-702 (Korea, Republic of); Kim, Byung-Joo, E-mail: ap2-kbj@hanmail.net [R& D Division, Korea Institute of Carbon Convergence Technology, Jeonju 561-844 (Korea, Republic of)

    2015-10-15

    Graphical abstract: We report preparation and characterization of silicon nitride (Si−N)-coated carbon fibers and their effects on thermal properties in composites. Thermally composites showed enhanced thermal conductivity increasing from up to 59% by the thermal network. - Highlights: • A new method of Si−N coating on carbon fibers was reported. • Silane layer were successfully converted to Si−N layer on carbon fiber surface. • Si−N formation was confirmed by FT-IR, XPS, and EDX. • Thermal conductivity of Si−N coated CF composites were enhanced to 0.59 W/mK. - Abstract: This study investigates the effect of silicon nitride (Si−N)-coated carbon fibers on the thermal conductivity of carbon-fiber-reinforced epoxy composite. The surface properties of the Si−N-coated carbon fibers (SiNCFs) were observe using Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy, and the thermal stability was analyzed using thermogravimetric analysis. SiNCFs were fabricated through the wet thermal treatment of carbon fibers (Step 1: silane finishing of the carbon fibers; Step 2: high-temperature thermal treatment in a N{sub 2}/NH{sub 3} environment). As a result, the Si−N belt was exhibited by SEM. The average thickness of the belt were 450–500 nm. The composition of Si−N was the mixture of Si−N, Si−O, and C−Si−N as confirmed by XPS. Thermal residue of the SiNCFs in air was enhanced from 3% to 50%. Thermal conductivity of the composites increased from 0.35 to 0.59 W/mK after Si−N coating on carbon surfaces.

  9. Preparation and characterization of electrochemically deposited carbon nitride films on silicon substrate

    International Nuclear Information System (INIS)

    Yan Xingbin; Xu Tao; Chen Gang; Yang Shengrong; Liu Huiwen; Xue Qunji

    2004-01-01

    Carbon nitride films (CN x films) were deposited on Si(100) substrates by the electrolysis of methanol-urea solution at high voltage, atmospheric pressure, and low temperature. The microstructure and morphology of the resulting CN x films were analysed by means of Raman spectroscopy, x-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectrometry (FTIR), x-ray diffraction (XRD), and atomic force microscopy. The tribological properties of the CN x films were examined on an UMT-2MT friction and wear test rig. The Raman spectrum showed two characteristic bands: a graphite G band and a disordered D band of carbon, which suggested the presence of an amorphous carbon matrix. XPS and FTIR measurements suggested the existence of both single and double carbon-nitride bonds in the film and the hydrogenation of the carbon nitride phase. The XRD spectrum showed various peaks of different d values, which could confirm the existence of the polycrystalline carbon nitride phase. The hydrogenated CN x films were compact and uniform, with a root mean square roughness of about 18 nm. The films showed excellent friction-reduction and wear-resistance, with the friction coefficient in the stable phase being about 0.08. In addition, the growth mechanism of the CN x films in liquid phase electro-deposition was discussed as well. It was assumed that the molecules of CH 3 OH and CO(NH 2 ) 2 were polarized under high electric field, and the CN x film was formed on the substrate through the reaction of the -CH 3 and -NH 2 groups on the cathode

  10. Joining technique of silicon nitride and silicon carbide in a mixture and/or in contact with high-melting metals and alloys

    International Nuclear Information System (INIS)

    Mueller-Zell, A.

    1980-01-01

    The following work gives a survey on possible joining techniques of silicon nitride (Si 3 N 4 ) and silicon carbide (SiC) in a mixture and/or in contact with high-melting metals and alloys. The problem arose because special ceramic materials such as Si 3 N 4 and SiC are to be used in gas turbines. The special ceramics in use may unavoidably come into contact with metals or the one hand, or form intended composite systems with them on the other hand, like e.g. the joining of a Si 3 N 4 disc with a metallic drive axis or ceramic blades with a metal wheel. The mixed body of X% ceramic (Si 3 N 4 , SiC) and Y% metal powder were prepared depending on the material combination at 1200 0 C-1750 0 C by hot-pressing or at 1200 0 C-2050 0 C by hot-pressing or pressureless sintering. The following possible ways were chosen as interlaminar bonding ceramic/metal/ceramic: on the one hand pressure welding (composite hot pressing) and the solid-state bonding in direct contact and by means of artificially included transition mixed layers, as well as material intermediate layers between metal and ceramic and on the other hand, soldering with active solder with molten phase. (orig./RW) [de

  11. Analytical and experimental evaluation of joining silicon nitride to metal and silicon carbide to metal for advanced heat engine applications. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kang, S.; Selverian, J.H.; O`Neil, D.; Kim, H. [GTE Labs., Inc., Waltham, MA (US); Kim, K. [Brown Univ., Providence, RI (US). Div. of Engineering

    1993-05-01

    This report summarizes the results of Phase 2 of Analytical and Experimental Evaluation of Joining Silicon Nitride to Metal and Silicon Carbide to Metal for Advanced Heat Engine Applications. A general methodology was developed to optimize the joint geometry and material systems for 650{degrees}C applications. Failure criteria were derived to predict the fracture of the braze and ceramic. Extensive finite element analyses (FEA) were performed to examine various joint geometries and to evaluate the affect of different interlayers on the residual stress state. Also, material systems composed of coating materials, interlayers, and braze alloys were developed for the program based on the chemical stability and strength of the joints during processing, and service. The FEA results were compared with experiments using two methods: (1) an idealized strength relationship of the ceramic, and (2) a probabilistic analysis of the ceramic strength (NASA CARES). The results showed that the measured strength of the joint reached 30--80% of the strength predicted by FEA. Also, potential high-temperature braze alloys were developed and evaluated for the high-temperature application of ceramic-metal joints. 38 tabs, 29 figs, 20 refs.

  12. Novel Cyclosilazane-Type Silicon Precursor and Two-Step Plasma for Plasma-Enhanced Atomic Layer Deposition of Silicon Nitride.

    Science.gov (United States)

    Park, Jae-Min; Jang, Se Jin; Lee, Sang-Ick; Lee, Won-Jun

    2018-03-14

    We designed cyclosilazane-type silicon precursors and proposed a three-step plasma-enhanced atomic layer deposition (PEALD) process to prepare silicon nitride films with high quality and excellent step coverage. The cyclosilazane-type precursor, 1,3-di-isopropylamino-2,4-dimethylcyclosilazane (CSN-2), has a closed ring structure for good thermal stability and high reactivity. CSN-2 showed thermal stability up to 450 °C and a sufficient vapor pressure of 4 Torr at 60 °C. The energy for the chemisorption of CSN-2 on the undercoordinated silicon nitride surface as calculated by density functional theory method was -7.38 eV. The PEALD process window was between 200 and 500 °C, with a growth rate of 0.43 Å/cycle. The best film quality was obtained at 500 °C, with hydrogen impurity of ∼7 atom %, oxygen impurity less than 2 atom %, low wet etching rate, and excellent step coverage of ∼95%. At 300 °C and lower temperatures, the wet etching rate was high especially at the lower sidewall of the trench pattern. We introduced the three-step PEALD process to improve the film quality and the step coverage on the lower sidewall. The sequence of the three-step PEALD process consists of the CSN-2 feeding step, the NH 3 /N 2 plasma step, and the N 2 plasma step. The H radicals in NH 3 /N 2 plasma efficiently remove the ligands from the precursor, and the N 2 plasma after the NH 3 plasma removes the surface hydrogen atoms to activate the adsorption of the precursor. The films deposited at 300 °C using the novel precursor and the three-step PEALD process showed a significantly improved step coverage of ∼95% and an excellent wet etching resistance at the lower sidewall, which is only twice as high as that of the blanket film prepared by low-pressure chemical vapor deposition.

  13. Silicon nitride and intrinsic amorphous silicon double antireflection coatings for thin-film solar cells on foreign substrates

    International Nuclear Information System (INIS)

    Li, Da; Kunz, Thomas; Wolf, Nadine; Liebig, Jan Philipp; Wittmann, Stephan; Ahmad, Taimoor; Hessmann, Maik T.; Auer, Richard; Göken, Mathias; Brabec, Christoph J.

    2015-01-01

    Hydrogenated intrinsic amorphous silicon (a-Si:H) was investigated as a surface passivation method for crystalline silicon thin film solar cells on graphite substrates. The results of the experiments, including quantum efficiency and current density-voltage measurements, show improvements in cell performance. This improvement is due to surface passivation by an a-Si:H(i) layer, which increases the open circuit voltage and the fill factor. In comparison with our previous work, we have achieved an increase of 0.6% absolute cell efficiency for a 40 μm thick 4 cm 2 aperture area on the graphite substrate. The optical properties of the SiN x /a-Si:H(i) stack were studied using spectroscopic ellipsometer techniques. Scanning transmission electron microscopy inside a scanning electron microscope was applied to characterize the cross section of the SiN x /a-Si:H(i) stack using focus ion beam preparation. - Highlights: • We report a 10.8% efficiency for thin-film silicon solar cell on graphite. • Hydrogenated intrinsic amorphous silicon was applied for surface passivation. • SiN x /a-Si:H(i) stacks were characterized by spectroscopic ellipsometer techniques. • Cross-section micrograph was obtained by scanning transmission electron microscopy. • Quantum efficiency and J-V measurements show improvements in the cell performance

  14. Studies of the composition, tribology and wetting behavior of silicon nitride films formed by pulsed reactive closed-field unbalanced magnetron sputtering

    International Nuclear Information System (INIS)

    Yao, Zh.Q.; Yang, P.; Huang, N.; Wang, J.; Wen, F.; Leng, Y.X.

    2006-01-01

    Silicon nitride films were formed by pulsed reactive closed-field unbalanced magnetron sputtering of high purity Si targets in an Ar-N 2 mixture. The effects of N 2 fraction on the chemical composition, and tribological and wetting behaviors were investigated. The films deposited at a high N 2 fraction were consistently N-rich. The surface microstructure changed from continuous granular surrounded by tiny void regions to a homogeneous and dense microstructure, and densitied as the N 2 fraction is increased. The as-deposited films have a relatively low friction coefficient and better wear resistance than 316L stainless steel under dry sliding friction and experienced only abrasive wear. The decreased surface roughness and increased nitrogen incorporation in the film give rise to increased contact angle with double-stilled water from 24 deg. to 49.6 deg. To some extent, the silicon nitride films deposited are hydrophilic in nature

  15. Luminescence properties of Ce3+-activated alkaline earth silicon nitride M2Si5N8 (M = Ca, Sr, Ba) materials

    NARCIS (Netherlands)

    Li, Y.Q.; With, de G.; Hintzen, H.T.J.M.

    2006-01-01

    The luminescence properties of Ce3+, Li+ or Na+ co-doped alkaline-earth silicon nitride M2Si5N8 (M=Ca, Sr, Ba) are reported. The solubility of Ce3+ and optical properties of M2-2xCexLixSi5N8 (x0.1) materials have been investigated as function of the cerium concentration by X-ray powder diffraction

  16. Matrix density effects on the mechanical properties of SiC fiber-reinforced silicon nitride matrix properties

    Science.gov (United States)

    Bhatt, Ramakrishna T.; Kiser, Lames D.

    1990-01-01

    The room temperature mechanical properties were measured for SiC fiber reinforced reaction-bonded silicon nitride composites (SiC/RBSN) of different densities. The composites consisted of approx. 30 vol percent uniaxially aligned 142 micron diameter SiC fibers (Textron SCS-6) in a reaction-bonded Si3N4 matrix. The composite density was varied by changing the consolidation pressure during RBSN processing and by hot isostatically pressing the SiC/RBSN composites. Results indicate that as the consolidation pressure was increased from 27 to 138 MPa, the average pore size of the nitrided composites decreased from 0.04 to 0.02 microns and the composite density increased from 2.07 to 2.45 gm/cc. Nonetheless, these improvements resulted in only small increases in the first matrix cracking stress, primary elastic modulus, and ultimate tensile strength values of the composites. In contrast, HIP consolidation of SiC/RBSN resulted in a fully dense material whose first matrix cracking stress and elastic modulus were approx. 15 and 50 percent higher, respectively, and ultimate tensile strength values were approx. 40 percent lower than those for unHIPed SiC/RBSN composites. The modulus behavior for all specimens can be explained by simple rule-of-mixture theory. Also, the loss in ultimate strength for the HIPed composites appears to be related to a degradation in fiber strength at the HIP temperature. However, the density effect on matrix fracture strength was much less than would be expected based on typical monolithic Si3N4 behavior, suggesting that composite theory is indeed operating. Possible practical implications of these observations are discussed.

  17. Damage Mechanisms and Controlled Crack Propagation in a Hot Pressed Silicon Nitride Ceramic. Ph.D. Thesis - Northwestern Univ., 1993

    Science.gov (United States)

    Calomino, Anthony Martin

    1994-01-01

    The subcritical growth of cracks from pre-existing flaws in ceramics can severely affect the structural reliability of a material. The ability to directly observe subcritical crack growth and rigorously analyze its influence on fracture behavior is important for an accurate assessment of material performance. A Mode I fracture specimen and loading method has been developed which permits the observation of stable, subcritical crack extension in monolithic and toughened ceramics. The test specimen and procedure has demonstrated its ability to generate and stably propagate sharp, through-thickness cracks in brittle high modulus materials. Crack growth for an aluminum oxide ceramic was observed to be continuously stable throughout testing. Conversely, the fracture behavior of a silicon nitride ceramic exhibited crack growth as a series of subcritical extensions which are interrupted by dynamic propagation. Dynamic initiation and arrest fracture resistance measurements for the silicon nitride averaged 67 and 48 J/sq m, respectively. The dynamic initiation event was observed to be sudden and explosive. Increments of subcritical crack growth contributed to a 40 percent increase in fracture resistance before dynamic initiation. Subcritical crack growth visibly marked the fracture surface with an increase in surface roughness. Increments of subcritical crack growth loosen ceramic material near the fracture surface and the fracture debris is easily removed by a replication technique. Fracture debris is viewed as evidence that both crack bridging and subsurface microcracking may be some of the mechanisms contributing to the increase in fracture resistance. A Statistical Fracture Mechanics model specifically developed to address subcritical crack growth and fracture reliability is used together with a damaged zone of material at the crack tip to model experimental results. A Monte Carlo simulation of the actual experiments was used to establish a set of modeling input

  18. Correlation of film density and wet etch rate in hydrofluoric acid of plasma enhanced atomic layer deposited silicon nitride

    Energy Technology Data Exchange (ETDEWEB)

    Provine, J., E-mail: jprovine@stanford.edu; Schindler, Peter; Kim, Yongmin; Walch, Steve P.; Kim, Hyo Jin [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Kim, Ki-Hyun [Manufacturing Technology Center, Samsung Electronics, Suwon, Gyeonggi-Do (Korea, Republic of); Prinz, Fritz B. [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States)

    2016-06-15

    The continued scaling in transistors and memory elements has necessitated the development of atomic layer deposition (ALD) of silicon nitride (SiN{sub x}), particularly for use a low k dielectric spacer. One of the key material properties needed for SiN{sub x} films is a low wet etch rate (WER) in hydrofluoric (HF) acid. In this work, we report on the evaluation of multiple precursors for plasma enhanced atomic layer deposition (PEALD) of SiN{sub x} and evaluate the film’s WER in 100:1 dilutions of HF in H{sub 2}O. The remote plasma capability available in PEALD, enabled controlling the density of the SiN{sub x} film. Namely, prolonged plasma exposure made films denser which corresponded to lower WER in a systematic fashion. We determined that there is a strong correlation between WER and the density of the film that extends across multiple precursors, PEALD reactors, and a variety of process conditions. Limiting all steps in the deposition to a maximum temperature of 350 °C, it was shown to be possible to achieve a WER in PEALD SiN{sub x} of 6.1 Å/min, which is similar to WER of SiN{sub x} from LPCVD reactions at 850 °C.

  19. DNA Physical Mapping via the Controlled Translocation of Single Molecules through a 5-10nm Silicon Nitride Nanopore

    Science.gov (United States)

    Stein, Derek; Reisner, Walter; Jiang, Zhijun; Hagerty, Nick; Wood, Charles; Chan, Jason

    2009-03-01

    The ability to map the binding position of sequence-specific markers, including transcription-factors, protein-nucleic acids (PNAs) or deactivated restriction enzymes, along a single DNA molecule in a nanofluidic device would be of key importance for the life-sciences. Such markers could give an indication of the active genes at particular stage in a cell's transcriptional cycle, pinpoint the location of mutations or even provide a DNA barcode that could aid in genomics applications. We have developed a setup consisting of a 5-10 nm nanopore in a 20nm thick silicon nitride film coupled to an optical tweezer setup. The translocation of DNA across the nanopore can be detected via blockades in the electrical current through the pore. By anchoring one end of the translocating DNA to an optically trapped microsphere, we hope to stretch out the molecule in the nanopore and control the translocation speed, enabling us to slowly scan across the genome and detect changes in the baseline current due to the presence of bound markers.

  20. Light emission in forward and reverse bias operation in OLED with amorphous silicon carbon nitride thin films

    Science.gov (United States)

    Reyes, R.; Cremona, M.; Achete, C. A.

    2011-01-01

    Amorphous silicon carbon nitride (a-SiC:N) thin films deposited by magnetron sputtering were used in the structure of an organic light emitting diode (OLED), obtaining an OLED operating in forward and reverse bias mode. The device consist of the heterojunction structure ITO/a-SiC:N/Hole Transport Layer (HTL)/ Electron Transport Layer (ETL)/a-SiC:N/Al. As hole transporting layer was used a thin film of 1-(3-methylphenyl)-1,2,3,4 tetrahydroquinoline - 6 - carboxyaldehyde - 1,1'- diphenylhydrazone (MTCD), while the tris(8-hydroxyquinoline aluminum) (Alq3) is used as electron transport and emitting layer. A significant increase in the voltage operation compared to the conventional ITO/MTCD/Alq3/Al structure was observed, so the onset of electroluminescence occurs at about 22 V in the forward and reverse bias mode of operation. The electroluminescence spectra is similar in both cases, only slightly shifted 0.14 eV to lower energies in relation to the conventional device.

  1. Oxidation effects on the mechanical properties of SiC fiber-reinforced reaction-bonded silicon nitride matrix composites

    Science.gov (United States)

    Bhatt, Ramakrishna T.

    1989-01-01

    The room temperature mechanical properties of SiC fiber reinforced reaction bonded silicon nitride composites were measured after 100 hrs exposure at temperatures to 1400 C in nitrogen and oxygen environments. The composites consisted of approx. 30 vol percent uniaxially aligned 142 micron diameter SiC fibers in a reaction bonded Si3N4 matrix. The results indicate that composites heat treated in a nitrogen environment at temperatures to 1400 C showed deformation and fracture behavior equivalent to that of the as-fabricated composites. Also, the composites heat treated in an oxidizing environment beyond 400 C yielded significantly lower tensile strength values. Specifically in the temperature range from 600 to 1000 C, composites retained approx. 40 percent of their as-fabricated strength, and those heat treated in the temperatures from 1200 to 1400 C retained 70 percent. Nonetheless, for all oxygen heat treatment conditions, composite specimens displayed strain capability beyond the matrix fracture stress; a typical behavior of a tough composite.

  2. Reprint of: Atmospheric scanning electron microscope observes cells and tissues in open medium through silicon nitride film.

    Science.gov (United States)

    Nishiyama, Hidetoshi; Suga, Mitsuo; Ogura, Toshihiko; Maruyama, Yuusuke; Koizumi, Mitsuru; Mio, Kazuhiro; Kitamura, Shinichi; Sato, Chikara

    2010-11-01

    Direct observation of subcellular structures and their characterization is essential for understanding their physiological functions. To observe them in open environment, we have developed an inverted scanning electron microscope with a detachable, open-culture dish, capable of 8 nm resolution, and combined with a fluorescence microscope quasi-simultaneously observing the same area from the top. For scanning electron microscopy from the bottom, a silicon nitride film window in the base of the dish maintains a vacuum between electron gun and open sample dish while allowing electrons to pass through. Electrons are backscattered from the sample and captured by a detector under the dish. Cells cultured on the open dish can be externally manipulated under optical microscopy, fixed, and observed using scanning electron microscopy. Once fine structures have been revealed by scanning electron microscopy, their component proteins may be identified by comparison with separately prepared fluorescence-labeled optical microscopic images of the candidate proteins, with their heavy-metal-labeled or stained ASEM images. Furthermore, cell nuclei in a tissue block stained with platinum-blue were successfully observed without thin-sectioning, which suggests the applicability of this inverted scanning electron microscope to cancer diagnosis. This microscope visualizes mesoscopic-scale structures, and is also applicable to non-bioscience fields including polymer chemistry. Copyright © 2010 Elsevier Inc. All rights reserved.

  3. Compositional analysis of silicon nitride films on Si and GaAs by backscattering spectrometry and nuclear resonance reaction analysis

    International Nuclear Information System (INIS)

    Kumar, Sanjiv; Raju, V.S.

    2004-01-01

    This paper describes the application of proton and α-backscattering spectrometry for the determination of atomic ratio of Si to N in 1100-5000 A silicon nitride films on Si and GaAs. The conventional α-Rutherford backscattering spectrometry is suitable for the analysis of films on Si; it is rather inadequate for films on GaAs due to higher background from the substrate. It is shown that these films can be analysed by 14 N(α,α) 14 N scattering with 3.5 MeV α-particles. Proton elastic scattering with enhanced cross sections for 28 Si(p,p) 28 Si and 14 N(p,p) 14 N scatterings, is also suitable for analysing films on GaAs. However, the analysis of films on Si by this technique is difficult due to interferences between the signals of Si from the film and the substrate. In addition, the hydrogen content in films is determined by 1 H( 19 F,αγ) 16 O nuclear reaction analysis using the resonance at 6.4 MeV. The combination of backscattering spectrometry with nuclear reaction analysis provides compositional analysis of ternary Si 1-(x+y) N x H y films

  4. Wide wavelength range tunable one-dimensional silicon nitride nano-grating guided mode resonance filter based on azimuthal rotation

    Directory of Open Access Journals (Sweden)

    Ryoji Yukino

    2017-01-01

    Full Text Available We describe wavelength tuning in a one dimensional (1D silicon nitride nano-grating guided mode resonance (GMR structure under conical mounting configuration of the device. When the GMR structure is rotated about the axis perpendicular to the surface of the device (azimuthal rotation for light incident at oblique angles, the conditions for resonance are different than for conventional GMR structures under classical mounting. These resonance conditions enable tuning of the GMR peak position over a wide range of wavelengths. We experimental demonstrate tuning over a range of 375 nm between 500 nm˜875 nm. We present a theoretical model to explain the resonance conditions observed in our experiments and predict the peak positions with show excellent agreement with experiments. Our method for tuning wavelengths is simpler and more efficient than conventional procedures that employ variations in the design parameters of structures or conical mounting of two-dimensional (2D GMR structures and enables a single 1D GMR device to function as a high efficiency wavelength filter over a wide range of wavelengths. We expect tunable filters based on this technique to be applicable in a wide range of fields including astronomy and biomedical imaging.

  5. Effect of Primary Recrystallized Microstructure and Nitriding on Secondary Recrystallization in Grain Oriented Silicon Steel by Low Temperature Slab Reheating

    Directory of Open Access Journals (Sweden)

    LIU Gong-tao

    2018-01-01

    Full Text Available Different primary recrystallized grain sizes were obtained by controlling decarburization process in grain oriented silicon steel produced by low temperature slab reheating technique. The effect of primary grain size on secondary recrystallization and magnetic properties was studied. The appropriate nitrogen content after nitriding was explored in case of very large primary grain size, and the effect of {411}〈148〉 primary recrystallized texture on the abnormal growth behavior was discussed. The results show that an increase in average primary grain size from 10μm to 15μm leads to an increase of secondary recrystallization temperature and a sharper Goss texture with higher magnetic permeability, in the condition of a very large average primary grain size of 28μm, the suitable amount of nitrogen increases to about 6×10-4. The {411}〈148〉 oriented grains in primary recrystallized microstructure can easily grow into larger sizes due to their size advantage, and thus hinder the abnormal growth of secondary grains, moreover, the hindering effect is more pronounced in the abnormal growth of Brass-oriented grains due to their misorientation with low migration rate other than Goss grains.

  6. Experimental evidence of the impact of rare-earth elements on particle growth and mechanical behaviour of silicon nitride

    International Nuclear Information System (INIS)

    Satet, Raphaelle L.; Hoffmann, Michael J.; Cannon, Rowland M.

    2006-01-01

    The impact of various rare-earth and related doping elements (R = Lu, Sc, Yb, Y, Sm, La) on the grain growth anisotropy and the mechanical properties of polycrystalline β-silicon nitride ceramics has been studied. Model experiments, in which Si 3 N 4 particles can grow freely in an R-Si-Mg-oxynitride glass matrix, show that, with increasing ionic radius of the additive, grain anisotropy increases due to non-linear growth kinetics. Toughness and strength are affected by the rare-earth element. Samples of equivalent grain sizes and morphologies yield an increasing toughness with increasing ion size of the R 3+ , reflecting an increasingly intergranular crack path. These samples are also strong and flaw tolerant, but the trends of strength and toughness do not exactly match. The choice of the rare-earth is essential to tailor microstructure, interfacial strength and mechanical properties. However, somewhat different trends for properties from IIIb and lanthanide additives indicate that more than the R 3+ size (i.e., purely ionic bond strength between R 3+ and its neighbours) is important. The electronic structure of the R-element is responsible for the type of dopant adsorption and the properties of the interface

  7. Light emission in forward and reverse bias operation in OLED with amorphous silicon carbon nitride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, R [Facultad de Ingenieria Quimica y Textil, Universidad Nacional de Ingenieria, Av. Tupac Amaru SN, Lima (Peru); Cremona, M [Departamento de Fisica, PontifIcia Universidade Catolica de Rio de Janeiro, PUC-Rio, Cx. Postal 38071, Rio de Janeiro, RJ, CEP 22453-970 (Brazil); Achete, C A, E-mail: rreyes@uni.edu.pe [Departamento de Engenheria Metalurgica e de Materiais, Universidade Federal do Rio de Janeiro, Cx. Postal 68505, Rio de Janeiro, RJ, CEP 21945-970 (Brazil)

    2011-01-01

    Amorphous silicon carbon nitride (a-SiC:N) thin films deposited by magnetron sputtering were used in the structure of an organic light emitting diode (OLED), obtaining an OLED operating in forward and reverse bias mode. The device consist of the heterojunction structure ITO/a-SiC:N/Hole Transport Layer (HTL)/ Electron Transport Layer (ETL)/a-SiC:N/Al. As hole transporting layer was used a thin film of 1-(3-methylphenyl)-1,2,3,4 tetrahydroquinoline - 6 - carboxyaldehyde - 1,1'- diphenylhydrazone (MTCD), while the tris(8-hydroxyquinoline aluminum) (Alq{sub 3}) is used as electron transport and emitting layer. A significant increase in the voltage operation compared to the conventional ITO/MTCD/Alq{sub 3}/Al structure was observed, so the onset of electroluminescence occurs at about 22 V in the forward and reverse bias mode of operation. The electroluminescence spectra is similar in both cases, only slightly shifted 0.14 eV to lower energies in relation to the conventional device.

  8. Light emission in forward and reverse bias operation in OLED with amorphous silicon carbon nitride thin films

    International Nuclear Information System (INIS)

    Reyes, R; Cremona, M; Achete, C A

    2011-01-01

    Amorphous silicon carbon nitride (a-SiC:N) thin films deposited by magnetron sputtering were used in the structure of an organic light emitting diode (OLED), obtaining an OLED operating in forward and reverse bias mode. The device consist of the heterojunction structure ITO/a-SiC:N/Hole Transport Layer (HTL)/ Electron Transport Layer (ETL)/a-SiC:N/Al. As hole transporting layer was used a thin film of 1-(3-methylphenyl)-1,2,3,4 tetrahydroquinoline - 6 - carboxyaldehyde - 1,1'- diphenylhydrazone (MTCD), while the tris(8-hydroxyquinoline aluminum) (Alq 3 ) is used as electron transport and emitting layer. A significant increase in the voltage operation compared to the conventional ITO/MTCD/Alq 3 /Al structure was observed, so the onset of electroluminescence occurs at about 22 V in the forward and reverse bias mode of operation. The electroluminescence spectra is similar in both cases, only slightly shifted 0.14 eV to lower energies in relation to the conventional device.

  9. Spontaneously-acoustic hypersound long-range stimulation of silicon nitride synthesis in silicon at argon ion irradiation

    CERN Document Server

    Demidov, E S; Markov, K A; Sdobnyakov, V V

    2001-01-01

    The work is dedicated to the nature of the average energy ions implantation process effect on the crystal defective system at the distances, exceeding by three-four orders the averagely projected ions run value. It is established that irradiation by the argon ions stimulated the Si sub 3 N sub 4 phase formation in the preliminarily nitrogen-saturated layers at the distances of approximately 600 mu m from the ions deceleration zone. It is supposed that there appear sufficiently effective pulse sources of the hypersonic shock waves in the area of the Ar sup + deceleration zone. These waves are the result of the jump-like origination and grid evolution of the loop-shaped dislocations and argon blisters as well as of the blisters explosion, The evaluations show that the peak pressure in wave due to the synchronized explosion of blisters in the nitrogen-saturated area on the reverse side of the silicon plate 600 mu m thick may exceed 10 sup 8 Pa and cause experimentally observed changes

  10. Co-implantation of carbon and nitrogen into silicon dioxide for synthesis of carbon nitride materials

    CERN Document Server

    Huang, M B; Nuesca, G; Moore, R

    2002-01-01

    Materials synthesis of carbon nitride has been attempted with co-implantation of carbon and nitrogen into thermally grown SiO sub 2. Following implantation of C and N ions to doses of 10 sup 1 sup 7 cm sup - sup 2 , thermal annealing of the implanted SiO sub 2 sample was conducted at 1000 degree sign C in an N sub 2 ambient. As evidenced in Fourier transform infrared measurements and X-ray photoelectron spectroscopy, different bonding configurations between C and N, including C-N single bonds, C=N double bonds and C=N triple bonds, were found to develop in the SiO sub 2 film after annealing. Chemical composition profiles obtained with secondary ion mass spectroscopy were correlated with the depth information of the chemical shifts of N 1s core-level electrons, allowing us to examine the formation of C-N bonding for different atomic concentration ratios between N and C. X-ray diffraction and transmission electron microscopy showed no sign of the formation of crystalline C sub 3 N sub 4 precipitates in the SiO ...

  11. Layer-by-layer composition and structure of silicon subjected to combined gallium and nitrogen ion implantation for the ion synthesis of gallium nitride

    Energy Technology Data Exchange (ETDEWEB)

    Korolev, D. S.; Mikhaylov, A. N.; Belov, A. I.; Vasiliev, V. K.; Guseinov, D. V.; Okulich, E. V. [Nizhny Novgorod State University (Russian Federation); Shemukhin, A. A. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation); Surodin, S. I.; Nikolitchev, D. E.; Nezhdanov, A. V.; Pirogov, A. V.; Pavlov, D. A.; Tetelbaum, D. I., E-mail: tetelbaum@phys.unn.ru [Nizhny Novgorod State University (Russian Federation)

    2016-02-15

    The composition and structure of silicon surface layers subjected to combined gallium and nitrogen ion implantation with subsequent annealing have been studied by the X-ray photoelectron spectroscopy, Rutherford backscattering, electron spin resonance, Raman spectroscopy, and transmission electron microscopy techniques. A slight redistribution of the implanted atoms before annealing and their substantial migration towards the surface during annealing depending on the sequence of implantations are observed. It is found that about 2% of atoms of the implanted layer are replaced with gallium bonded to nitrogen; however, it is impossible to detect the gallium-nitride phase. At the same time, gallium-enriched inclusions containing ∼25 at % of gallium are detected as candidates for the further synthesis of gallium-nitride inclusions.

  12. High temperature and low pressure chemical vapor deposition of silicon nitride on AlGaN: Band offsets and passivation studies

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, Pramod; Washiyama, Shun; Kaess, Felix; Hernandez-Balderrama, Luis H.; Haidet, Brian B.; Alden, Dorian; Franke, Alexander; Sarkar, Biplab; Kohn, Erhard; Collazo, Ramon; Sitar, Zlatko [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7919 (United States); Hayden Breckenridge, M. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7919 (United States); REU, Physics Department at Wofford College, Spartanburg, South Carolina 29303 (United States)

    2016-04-14

    In this work, we employed X-ray photoelectron spectroscopy to determine the band offsets and interface Fermi level at the heterojunction formed by stoichiometric silicon nitride deposited on Al{sub x}Ga{sub 1-x}N (of varying Al composition “x”) via low pressure chemical vapor deposition. Silicon nitride is found to form a type II staggered band alignment with AlGaN for all Al compositions (0 ≤ x ≤ 1) and present an electron barrier into AlGaN even at higher Al compositions, where E{sub g}(AlGaN) > E{sub g}(Si{sub 3}N{sub 4}). Further, no band bending is observed in AlGaN for x ≤ 0.6 and a reduced band bending (by ∼1 eV in comparison to that at free surface) is observed for x > 0.6. The Fermi level in silicon nitride is found to be at 3 eV with respect to its valence band, which is likely due to silicon (≡Si{sup 0/−1}) dangling bonds. The presence of band bending for x > 0.6 is seen as a likely consequence of Fermi level alignment at Si{sub 3}N{sub 4}/AlGaN hetero-interface and not due to interface states. Photoelectron spectroscopy results are corroborated by current-voltage-temperature and capacitance-voltage measurements. A shift in the interface Fermi level (before band bending at equilibrium) from the conduction band in Si{sub 3}N{sub 4}/n-GaN to the valence band in Si{sub 3}N{sub 4}/p-GaN is observed, which strongly indicates a reduction in mid-gap interface states. Hence, stoichiometric silicon nitride is found to be a feasible passivation and dielectric insulation material for AlGaN at any composition.

  13. Bacterial populations on silicone hydrogel and hydrogel contact lenses after swimming in a chlorinated pool.

    Science.gov (United States)

    Choo, Jennifer; Vuu, Kathy; Bergenske, Peter; Burnham, Kara; Smythe, Jennifer; Caroline, Patrick

    2005-02-01

    A number of reports have indicated an association between swimming with contact lenses and subsequent eye infection. This study tests whether a hydrophilic contact lens worn while swimming accumulates bacteria present in the water. It was of interest to determine whether lens type (silicone hydrogel vs. hydrogel) affected the result. Fifteen healthy noncontact lens wearers swam for 30 minutes with a silicone hydrogel lens (PureVision, Bausch & Lomb, Rochester, NY) on one eye and a hydrogel lens (Acuvue 2, Vistakon Inc., Jacksonville, FL) on the other. Lenses were removed aseptically and placed in sterile vials 10 minutes after the subjects left the water. Microbial growth was enumerated for total numbers of colonies and categorized by species present. Numbers of colonies were compared between the two lens groups and with a water sample taken from the pool at the time of the experiment. Eight of the subjects returned on a different day and wore new lenses for 50 minutes in normal room conditions. Two lenses were lost while swimming. Twenty-seven of the remaining 28 lenses worn while swimming showed colonization, principally with Staphylococcus epidermidis, which was also by far the most common species identified from the water itself. Small numbers of Staphylococcus aureus and Streptococcus salivarius were also present in the water and on the lenses. Numbers of colonies varied among subjects (range, 0 to 230), but no differences were observed between the two lens groups. Lenses removed after 30 minutes of wear without swimming were mostly sterile, with 3 of 16 lenses showing just two colonies each. It appears that wearing a hydrophilic lens while swimming allows accumulation of microbial organisms on or in the lens, regardless of lens material. Swimmers should be advised to wear tight-fitting goggles if lenses are worn while swimming, and thorough disinfection of the lenses before overnight wear seems prudent.

  14. Effect of Silicon Nitride Incorporation on Microstructure and Hardness of Ni-Co Metal Matrix Nanocomposite

    Directory of Open Access Journals (Sweden)

    Ridwan

    2015-01-01

    Full Text Available Ni-Co-Si3N4 nanocomposite coatings were prepared by electrodeposition technique. The deposition was performed at 50 mA cm-2 on copper substrate. The working temperature of electrodepostion was constant at 500C in an acidic environment of pH 4. The effects of silicon in the nickel-cobalt metal matrix composite were investigated. Energy dispersive X-ray spectroscopy was used to determine the composition. The Co content in the coatings is in the range 27-49 at.%. The phase present in the Ni-Co-Si3N4 were examined with an X-ray diffraction analysis. All the reflection patterns indicate that the coatings are having face-centered cubic (fcc structure. The microhardness of the Ni-Co-Si3N4 nanocomposite coating increases with increasing silicon content. The microhardness of the Ni-Co-Si3N4 nanocomposite coating increased from 549 HV for Nickel-cobalt alloy coating to 641 HV for Ni-Co-Si3N4 nanocomposite coating with 5.47 at.% Si.

  15. In situ characterization of thin film growth: Boron nitride on silicon

    International Nuclear Information System (INIS)

    Fukarek, W.

    2001-01-01

    Real-time ellipsometry (RTE) in combination with particle flux measurement is applied to ion beam assisted deposition of boron nitride (BN) films. RTE is used as a tool for process diagnostic to improve the deposition stability. A novel technique for the determination of absolute density depth profiles from dynamic growth rate data and film forming particle flux is employed. From real-time cantilever curvature measurement and simultaneously recorded film thickness data instantaneous stress depth profiles are derived with a depth resolution in the nm range. The synergistic effects on the information obtained from RTE, particle flux, and cantilever bending data are demonstrated. The density of turbostratic BN (tBN) is found to increase slightly with film thickness while the compressive stress decreases, indicating an increasing quality and/or size of crystallites in the course of film growth. Refractive index and density depth profiles in cubic BN (cBN) films correspond perfectly to structural information obtained from dark field transmission electron microscope graphs. The established tBN/cBN two-layer model is found to be a crude approximation that has to be replaced by a three-layer model including nucleation, grain growth, and coalescence of cBN. The instantaneous compressive stress in a homogeneous tBN film is found to decrease, while the density increases during growth. The instantaneous compressive stress depth profiles in cBN films are more complex and not easy to understand but reliable information on the structural evolution during growth can be extracted

  16. Improving optical properties of silicon nitride films to be applied in the middle infrared optics by a combined high-power impulse/unbalanced magnetron sputtering deposition technique.

    Science.gov (United States)

    Liao, Bo-Huei; Hsiao, Chien-Nan

    2014-02-01

    Silicon nitride films are prepared by a combined high-power impulse/unbalanced magnetron sputtering (HIPIMS/UBMS) deposition technique. Different unbalance coefficients and pulse on/off ratios are applied to improve the optical properties of the silicon nitride films. The refractive indices of the Si3N4 films vary from 2.17 to 2.02 in the wavelength ranges of 400-700 nm, and all the extinction coefficients are smaller than 1×10(-4). The Fourier transform infrared spectroscopy and x-ray diffractometry measurements reveal the amorphous structure of the Si3N4 films with extremely low hydrogen content and very low absorption between the near IR and middle IR ranges. Compared to other deposition techniques, Si3N4 films deposited by the combined HIPIMS/UBMS deposition technique possess the highest refractive index, the lowest extinction coefficient, and excellent structural properties. Finally a four-layer coating is deposited on both sides of a silicon substrate. The average transmittance from 3200 to 4800 nm is 99.0%, and the highest transmittance is 99.97% around 4200 nm.

  17. Efficient and Stable CsPbBr3 Quantum-Dot Powders Passivated and Encapsulated with a Mixed Silicon Nitride and Silicon Oxide Inorganic Polymer Matrix.

    Science.gov (United States)

    Yoon, Hee Chang; Lee, Soyoung; Song, Jae Kyu; Yang, Heesun; Do, Young Rag

    2018-04-11

    Despite the excellent optical features of fully inorganic cesium lead halide (CsPbX 3 ) perovskite quantum dots (PeQDs), their unstable nature has limited their use in various optoelectronic devices. To mitigate the instability issues of PeQDs, we demonstrate the roles of dual-silicon nitride and silicon oxide ligands of the polysilazane (PSZ) inorganic polymer to passivate the surface defects and form a barrier layer coated onto green CsPbBr 3 QDs to maintain the high photoluminescence quantum yield (PLQY) and improve the environmental stability. The mixed SiN x /SiN x O y /SiO y passivated and encapsulated CsPbBr 3 /PSZ core/shell composite can be prepared by a simple hydrolysis reaction involving the addition of adding PSZ as a precursor and a slight amount of water into a colloidal CsPbBr 3 QD solution. The degree of the moisture-induced hydrolysis reaction of PSZ can affect the compositional ratio of SiN x , SiN x O y , and SiO y liganded to the surfaces of the CsPbBr 3 QDs to optimize the PLQY and the stability of CsPbBr 3 /PSZ core/shell composite, which shows a high PLQY (∼81.7%) with improved thermal, photo, air, and humidity stability as well under coarse conditions where the performance of CsPbBr 3 QDs typically deteriorate. To evaluate the suitability of the application of the CsPbBr 3 /PSZ powder to down-converted white-light-emitting diodes (DC-WLEDs) as the backlight of a liquid crystal display (LCD), we fabricated an on-package type of tricolor-WLED by mixing the as-synthesized green CsPbBr 3 /PSZ composite powder with red K 2 SiF 6 :Mn 4+ phosphor powder and a poly(methyl methacrylate)-encapsulating binder and coating this mixed paste onto a cup-type blue LED. The fabricated WLED show high luminous efficacy of 138.6 lm/W (EQE = 51.4%) and a wide color gamut of 128% and 111% without and with color filters, respectively, at a correlated color temperature of 6762 K.

  18. High resolution medium energy ion scattering study of silicon oxidation and oxy nitridation

    International Nuclear Information System (INIS)

    Gusev, E.P.; Lu, H.C.; Garfunkel, E.; Gustafsson, T.

    1998-01-01

    Full text: Silicon oxide is likely to remain the material of choice for gate oxides in microelectronics for the foreseeable future. As device become ever smaller and faster, the thickness of these layers in commercial products is predicted to be less than 50 Angstroms in just a few years. An understanding of such devices will therefore likely to be based on microscopic concepts and should now be investigated by atomistic techniques. With medium energy ion scattering (MEIS) using an electrostatic energy analyzer, depth profiling of thin (<60 Angstroms) silicon oxide films on Si(100) with 3 - 5 Angstroms depth resolution in the near region has been done. The growth mechanism of thin oxide films on Si(100) has been studied, using sequential oxygen isotope exposures. It is found that the oxide films are stoichiometric to within approx. 10 Angstroms of the interface. It is also found that the oxidation reactions occur at the surface, in the transition region and at interface, with only the third region being included in the conventional (Deal-Grove) model for oxide formation. Nitrogen is sometimes added to gate oxides, as it has been found empirically that his improves some of the electrical properties. The role, location and even the amount of nitrogen that exists in such films are poorly understood, and represent interesting analytical challenges. MEIS data will be presented that address these questions, measured for a number of different processing conditions. We have recently demonstrated how to perform nitrogen nano-engineering in such ultrathin gate dielectrics, and these results will also be discussed

  19. Surface topography of silicon nitride affects antimicrobial and osseointegrative properties of tibial implants in a murine model.

    Science.gov (United States)

    Ishikawa, Masahiro; de Mesy Bentley, Karen L; McEntire, Bryan J; Bal, B Sonny; Schwarz, Edward M; Xie, Chao

    2017-12-01

    While silicon nitride (Si 3 N 4 ) is an antimicrobial and osseointegrative orthopaedic biomaterial, the contribution of surface topography to these properties is unknown. Using a methicillin-resistant strain of Staphylococcus aureus (MRSA), this study evaluated Si 3 N 4 implants in vitro utilizing scanning electron microscopy (SEM) with colony forming unit (CFU) assays, and later in an established in vivo murine tibia model of implant-associated osteomyelitis. In vitro, the "as-fired" Si 3 N 4 implants displayed significant reductions in adherent bacteria versus machined Si 3 N 4 (2.6 × 10 4 vs. 8.7 × 10 4 CFU, respectively; p SEM imaging demonstrated that MRSA cannot directly adhere to native as-fired Si 3 N 4 . Subsequently, a cross-sectional study was completed in which sterile or MRSA contaminated as-fired and machined Si 3 N 4 implants were inserted into the tibiae of 8-week old female Balb/c mice, and harvested on day 1, 3, 5, 7, 10, or 14 post-operatively for SEM. The findings demonstrated that the antimicrobial activity of the as-fired implants resulted from macrophage clearance of the bacteria during biofilm formation on day 1, followed by osseointegration through the apparent recruitment of mesenchymal stem cells on days 3-5, which differentiated into osteoblasts on days 7-14. In contrast, the antimicrobial behavior of the machined Si 3 N 4 was due to repulsion of the bacteria, a phenomenon that also limited osteogenesis, as host cells were also unable to adhere to the machined surface. Taken together, these results suggest that the in vivo biological behavior of Si 3 N 4 orthopaedic implants is driven by critical features of their surface nanotopography. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3413-3421, 2017. © 2017 Wiley Periodicals, Inc.

  20. Hot-pressed silicon nitride with various lanthanide oxides as sintering additives

    Science.gov (United States)

    Ueno, K.; Toibana, Y.

    1984-01-01

    The effects of addition of various lanthanide oxides and their mixture with Y2O3 on the sintering of Si3N4 were investigated. The addition of simple and mixed lanthanide oxides promoted the densification of Si3N4 in hot-pressing at 1800 C under 300-400kg/ centimeters squared for 60 min. The crystallization of yttrium and lanthanide-silicon oxynitrides which was observed inn the sintered body containing yttrium-lanthanide mixed oxides as additives led to the formation of a highly refractory Si3N4 ceramic having a bending strength of 82 and 84 kg/millimeters squared at room temperature and 1300 C respectively. In a Y2O3+La2O3 system, a higher molar ratio of La2O3 to Y2O3 gave a higher hardness and strength at high temperatures. It was found that 90 min was an optimum sintering time for the highest strength.

  1. Effects of silicon-nitride passivation on the electrical behavior of 0.1-μm pseudomorphic high-electron-mobility transistors

    International Nuclear Information System (INIS)

    Oh, Jung-Hun; Sul, Woo-Suk; Han, Hyo-Jong; Jang, Hae-Kang; Son, Myung-Sik; Rhee, Jin-Koo; Kim, Sam- Dong

    2004-01-01

    We examine the effects of surface state formation due to silicon-nitride passivation on the electrical characteristics of GaAs-based 0.1-μm pseudomorphic high-electron-mobility transistors (pHEMTs). In this study, DC and noise characteristic are investigated before and after the passivation of the pHEMTs. After the passivation, we observe significant degradation of noise performance in the frequency range of 55 - 62 GHz. We also observe clear increases in the drain-source saturation current at a gate voltage of 0 V and in the extrinsic transconductance at a drain voltage of 1 V from 325 and 264 to 365 mA/mm and 304 mS/mm, respectively, with no significant variation in pinchoff voltage. We propose that the observed variations in the DC and the noise characteristics are due to the positively charged surface state after deposition of the silicon nitride passivation film. Hydrodynamic device model simulations were performed based upon the proposed mechanisms for the change in electrical behavior, and the calculated results show good agreement with the experimental results.

  2. Silicon nitride and silicon etching by CH{sub 3}F/O{sub 2} and CH{sub 3}F/CO{sub 2} plasma beams

    Energy Technology Data Exchange (ETDEWEB)

    Kaler, Sanbir S.; Lou, Qiaowei; Donnelly, Vincent M., E-mail: vmdonnelly@uh.edu; Economou, Demetre J., E-mail: economou@uh.edu [Department of Chemical and Biomolecular Engineering, Plasma Processing Laboratory, University of Houston, Houston, Texas 77204 (United States)

    2016-07-15

    Silicon nitride (SiN, where Si:N ≠ 1:1) films low pressure-chemical vapor deposited on Si substrates, Si films on Ge on Si substrates, and p-Si samples were exposed to plasma beams emanating from CH{sub 3}F/O{sub 2} or CH{sub 3}F/CO{sub 2} inductively coupled plasmas. Conditions within the plasma beam source were maintained at power of 300 W (1.9 W/cm{sup 3}), pressure of 10 mTorr, and total gas flow rate of 10 sccm. X-ray photoelectron spectroscopy was used to determine the thicknesses of Si/Ge in addition to hydrofluorocarbon polymer films formed at low %O{sub 2} or %CO{sub 2} addition on p-Si and SiN. Polymer film thickness decreased sharply as a function of increasing %O{sub 2} or %CO{sub 2} addition and dropped to monolayer thickness above the transition point (∼48% O{sub 2} or ∼75% CO{sub 2}) at which the polymer etchants (O and F) number densities in the plasma increased abruptly. The C(1s) spectra for the polymer films deposited on p-Si substrates appeared similar to those on SiN. Spectroscopic ellipsometry was used to measure the thickness of SiN films etched using the CH{sub 3}F/O{sub 2} and CH{sub 3}F/CO{sub 2} plasma beams. SiN etching rates peaked near 50% O{sub 2} addition and 73% CO{sub 2} addition. Faster etching rates were measured in CH{sub 3}F/CO{sub 2} than CH{sub 3}F/O{sub 2} plasmas above 70% O{sub 2} or CO{sub 2} addition. The etching of Si stopped after a loss of ∼3 nm, regardless of beam exposure time and %O{sub 2} or %CO{sub 2} addition, apparently due to plasma assisted oxidation of Si. An additional GeO{sub x}F{sub y} peak was observed at 32.5 eV in the Ge(3d) region, suggesting deep penetration of F into Si, under the conditions investigated.

  3. The influence of powder composition and sintering temperature on transformation kinetics, structure and mechanical properties of hot-pressed silicon nitride

    International Nuclear Information System (INIS)

    Knoch, H.; Ziegler, G.

    1977-01-01

    The strength at room temperature of hot-pressed silicon nitride is strongly dependent on the structure which in turn depends on powder composition and process parameters. Connections between production conditions (MgO content, pressing temperature, pressing time), structure (α/β content and morphology), and the properties at room temperature are discussed. The growth of oblong β grains - as a direct result of phase transition from α- to β-Si 3 N 4 - results in microstructural meshing and thus in a higher strength. Optimum mechanical properties are achieved after full phase transformation and with a microstructure as fine as possible. The direct connection between strength and transformed β fraction indicates a possible way for a relatively fast determination of optimum properties for a given initial powder. (orig.) [de

  4. Relative SHG measurements of metal thin films: Gold, silver, aluminum, cobalt, chromium, germanium, nickel, antimony, titanium, titanium nitride, tungsten, zinc, silicon and indium tin oxide

    Directory of Open Access Journals (Sweden)

    Franklin Che

    Full Text Available We have experimentally measured the surface second-harmonic generation (SHG of sputtered gold, silver, aluminum, zinc, tungsten, copper, titanium, cobalt, nickel, chromium, germanium, antimony, titanium nitride, silicon and indium tin oxide thin films. The second-harmonic response was measured in reflection using a 150 fs p-polarized laser pulse at 1561 nm. We present a clear comparison of the SHG intensity of these films relative to each other. Our measured relative intensities compare favorably with the relative intensities of metals with published data. We also report for the first time to our knowledge the surface SHG intensity of tungsten and antimony relative to that of well known metallic thin films such as gold and silver. Keywords: Surface second-harmonic generation, Nonlinear optics, Metal thin films

  5. Theoretical study of charge trapping levels in silicon nitride using the LDA-1/2 self-energy correction scheme for excited states

    International Nuclear Information System (INIS)

    Patrocinio, Weslley S.; Ribeiro, Mauro; Fonseca, Leonardo R.C.

    2012-01-01

    Silicon nitride, with a permittivity mid-way between SiO 2 and common high-k materials such as HfO 2 , is widely used in microelectronics as an insulating layer on top of oxides where it serves as an impurity barrier with the positive side effect of increasing the dielectric constant of the insulator when it is SiO 2 . It is also employed as charge storage in nonvolatile memory devices thanks to its high concentration of charge traps. However, in the case of memories, it is still unclear which defects are responsible for charge trapping and what is the impact of defect concentration on the structural and electronic properties of SiN x . Indeed, for the amorphous phase the band gap was measured in the range 5.1–5.5 eV, with long tails in the density of states penetrating the gap region. It is still not clear which defects are responsible for the tails. On the other hand, the K-center defects have been associated with charge trapping, though its origin is assigned to one Si back bond. To investigate the contribution of defect states to the band edge tails and band gap states, we adopted the β phase of stoichiometric silicon nitride (β-Si 3 N 4 ) as our model material and calculated its electronic properties employing ab initio DFT/LDA simulations with self-energy correction to improve the location of defect states in the SiN x band gap through the correction of the band gap underestimation typical of DFT/LDA. We considered some important defects in SiN x , as the Si anti-site and the N vacancy with H saturation, in two defect concentrations. The location of our calculated defect levels in the band gap correlates well with the available experimental data, offering a structural explanation to the measured band edge tails and charge trapping characteristics.

  6. Preparation and properties of bisphenol-F based boron-phenolic resin/modified silicon nitride composites and their usage as binders for grinding wheels

    International Nuclear Information System (INIS)

    Lin, Chun-Te; Lee, Hsun-Tsing; Chen, Jem-Kun

    2015-01-01

    Highlights: • Bisphenol-F based boron-phenolic resins (B-BPF) with B−O bonds were synthesized. • The modified silicon nitride (m-SiN) was well dispersed and adhered in the B-BPF. • B-BPF/m-SiN composites have good thermal resistance and mechanical properties. • The grinding wheels bound by B-BPF/m-SiN have excellent grinding quality. - Abstract: In this study, phenolic resins based on bisphenol-F (BPF) were synthesized. Besides, ammonium borate was added in the synthesis process of BPF to form the bisphenol-F based boron-phenolic resins (B-BPF). The glass transition temperature, thermal resistance, flexural strength and hardness of B-BPF are respectively higher than those of BPF. This is due to the presence of new cross-link B−O bonds in the B-BPF. In addition, the 3-aminopropyltriethoxysilane modified silicon nitride powders (m-SiN) were fully mixed with B-BPF to form the B-BPF/m-SiN composites. The thermal resistance and mechanical properties of the B-BPF/m-SiN are promoted by the well-dispersed and well-adhered m-SiN in these novel polymer/ceramics composites. The results of grinding experiments indicate that the grinding wheels bound by the B-BPF/m-SiN have better grinding quality than those bound by the BPF. Thus the B-BPF/m-SiN composites are better binding media than the BPF resins

  7. Determination of molecular stopping cross section of {sup 12}C, {sup 16}O, {sup 28}Si, {sup 35}Cl, {sup 58}Ni, {sup 79}Br, and {sup 127}I in silicon nitride

    Energy Technology Data Exchange (ETDEWEB)

    Barradas, N.P., E-mail: nunoni@ctn.ist.utl.pt [Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Unversidade de Lisboa, Estrada Nacional 10 ao km 139.7, 2695-066 Bobadela LRS (Portugal); Bergmaier, A. [Institut für Angewandte Physik und Messtechnik, Fakultät für Luft und Raumfahrttechnik, Werner-Heisenberg-Weg 39, D-85577 Neubiberg (Germany); Mizohata, K. [Department of Physics, University of Helsinki, P.O. Box 43, FI-00014 University of Helsinki (Finland); Msimanga, M. [iThemba LABS Gauteng, National Research Foundation, Private Bag 11, WITS 2050, Johannesburg (South Africa); Department of Physics, Tshwane University of Technology, Private Bag X680, Pretoria 0001 (South Africa); Räisänen, J. [Department of Physics, University of Helsinki, P.O. Box 43, FI-00014 University of Helsinki (Finland); Sajavaara, T. [Department of Physics, University of Jyväskylä, Survontie 9, 40014 Jyväskylä (Finland); Simon, A. [International Atomic Energy Agency, Division of Physical and Chemical Sciences, Vienna International Centre, P.O. Box 100, A-1400 Vienna (Austria); Institute of Nuclear Research of the Hungarian Academy of Sciences, (ATOMKI), P.O. Box 51, H-4001 Debrecen (Hungary)

    2015-10-01

    Silicon nitride is a technologically important material in a range of applications due to a combination of important properties. Ion beam analysis techniques, and in particular, heavy ion elastic recoil detection analysis can be used to determine the stoichiometry of silicon nitride films, which often deviates from the ideal Si{sub 3}N{sub 4}, as well as the content of impurities such as hydrogen, even in the presence of other materials or in a matrix containing heavier elements. Accurate quantification of IBA results depends on the basic data used in the data analysis. Quantitative depth profiling relies on the knowledge of the stopping power cross sections of the materials studied for the ions involved, which in the case of HI-ERDA is both the primary beam, and the recoiled species. We measured the stopping cross section of {sup 12}C, {sup 16}O, {sup 28}Si, {sup 35}Cl, {sup 58}Ni, {sup 79}Br, and {sup 127}I in a well-characterised silicon nitride membrane. The measurements were made by independent groups utilising different experimental setups and methods. In some cases there is extensive overlap of the energy range in different experiments, allowing a comparison of the different results. The four independent data sets reported in this work are in excellent agreement with each other, in the cases where similar energy ranges were measured. On the other hand, the data are in most cases higher than calculations made with the interpolative schemes SRIM and MSTAR together with the Bragg rule. Better agreement is found with MSTAR in some of the cases studied. This work is a significant extension of the heavy ion stopping power data base for silicon nitride.

  8. Enhancing the wettability of high aspect-ratio through-silicon vias lined with LPCVD silicon nitride or PE-ALD titanium nitride for void-free bottom-up copper electroplating

    NARCIS (Netherlands)

    Saadaoui, M.; Zeijl, H. van; Wien, W.H.A.; Pham, H.T.M.; Kwakernaak, C.; Knoops, H.C.M.; Erwin Kessels, W.M.M.; Sanden, R.M.C.M. van de; Voogt, F.C.; Roozeboom, F.; Sarro, P.M.

    2011-01-01

    One of the critical steps toward producing void-free and uniform bottom-up copper electroplating in high aspect-ratio (AR) through-silicon vias (TSVs) is the ability of the copper electrolyte to spontaneously flow through the entire depth of the via. This can be accomplished by reducing the

  9. Enhancing the Wettability of High Aspect-Ratio Through-Silicon Vias Lined with LPCVD Silicon Nitride or PE-ALD Titanium Nitride for Void-Free Bottom-Up Copper Electroplating

    NARCIS (Netherlands)

    Saadaoui, M.; van Zeijl, H.; Wien, W. H. A.; Pham, H. T. M.; Kwakernaak, C.; Knoops, H. C. M.; Kessels, W. M. M.; R. van de Sanden,; Voogt, F. C.; Roozeboom, F.; Sarro, P. M.

    2011-01-01

    One of the critical steps toward producing void-free and uniform bottom-up copper electroplating in high aspect-ratio (AR) through-silicon vias (TSVs) is the ability of the copper electrolyte to spontaneously flow through the entire depth of the via. This can be accomplished by reducing the

  10. The SNAP trial: a double blind multi-center randomized controlled trial of a silicon nitride versus a PEEK cage in transforaminal lumbar interbody fusion in patients with symptomatic degenerative lumbar disc disorders: study protocol

    Science.gov (United States)

    2014-01-01

    Background Polyetheretherketone (PEEK) cages have been widely used in the treatment of lumbar degenerative disc disorders, and show good clinical results. Still, complications such as subsidence and migration of the cage are frequently seen. A lack of osteointegration and fibrous tissues surrounding PEEK cages are held responsible. Ceramic implants made of silicon nitride show better biocompatible and osteoconductive qualities, and therefore are expected to lower complication rates and allow for better fusion. Purpose of this study is to show that fusion with the silicon nitride cage produces non-inferior results in outcome of the Roland Morris Disability Questionnaire at all follow-up time points as compared to the same procedure with PEEK cages. Methods/Design This study is designed as a double blind multi-center randomized controlled trial with repeated measures analysis. 100 patients (18–75 years) presenting with symptomatic lumbar degenerative disorders unresponsive to at least 6 months of conservative treatment are included. Patients will be randomly assigned to a PEEK cage or a silicon nitride cage, and will undergo a transforaminal lumbar interbody fusion with pedicle screw fixation. Primary outcome measure is the functional improvement measured by the Roland Morris Disability Questionnaire. Secondary outcome parameters are the VAS leg, VAS back, SF-36, Likert scale, neurological outcome and radiographic assessment of fusion. After 1 year the fusion rate will be measured by radiograms and CT. Follow-up will be continued for 2 years. Patients and clinical observers who will perform the follow-up visits will be blinded for type of cage used during follow-up. Analyses of radiograms and CT will be performed independently by two experienced radiologists. Discussion In this study a PEEK cage will be compared with a silicon nitride cage in the treatment of symptomatic degenerative lumbar disc disorders. To our knowledge, this is the first randomized controlled

  11. III-nitride disk-in-nanowire 1.2 μm monolithic diode laser on (001)silicon

    KAUST Repository

    Hazari, Arnab

    2015-11-12

    III-nitride nanowirediodeheterostructures with multiple In0.85Ga0.15N disks and graded InGaN mode confining regions were grown by molecular beam epitaxy on (001)Si substrates. The aerial density of the 60 nm nanowires is ∼3 × 1010 cm−2. A radiative recombination lifetime of 1.84 ns in the disks is measured by time-resolved luminescence measurements. Edge-emitting nanowire lasers have been fabricated and characterized. Measured values of Jth, T0, and dg/dn in these devices are 1.24 kA/cm2, 242 K, and 5.6 × 10−17 cm2, respectively. The peak emission is observed at ∼1.2 μm.

  12. Silicon nitride grids are compatible with correlative negative staining electron microscopy and tip-enhanced Raman spectroscopy for use in the detection of micro-organisms.

    Science.gov (United States)

    Lausch, V; Hermann, P; Laue, M; Bannert, N

    2014-06-01

    Successive application of negative staining transmission electron microscopy (TEM) and tip-enhanced Raman spectroscopy (TERS) is a new correlative approach that could be used to rapidly and specifically detect and identify single pathogens including bioterrorism-relevant viruses in complex samples. Our objective is to evaluate the TERS-compatibility of commonly used electron microscopy (EM) grids (sample supports), chemicals and negative staining techniques and, if required, to devise appropriate alternatives. While phosphortungstic acid (PTA) is suitable as a heavy metal stain, uranyl acetate, paraformaldehyde in HEPES buffer and alcian blue are unsuitable due to their relatively high Raman scattering. Moreover, the low thermal stability of the carbon-coated pioloform film on copper grids (pioloform grids) negates their utilization. The silicon in the cantilever of the silver-coated atomic force microscope tip used to record TERS spectra suggested that Si-based grids might be employed as alternatives. From all evaluated Si-based TEM grids, the silicon nitride (SiN) grid was found to be best suited, with almost no background Raman signals in the relevant spectral range, a low surface roughness and good particle adhesion properties that could be further improved by glow discharge. Charged SiN grids have excellent particle adhesion properties. The use of these grids in combination with PTA for contrast in the TEM is suitable for subsequent analysis by TERS. The study reports fundamental modifications and optimizations of the negative staining EM method that allows a combination with near-field Raman spectroscopy to acquire a spectroscopic signature from nanoscale biological structures. This should facilitate a more precise diagnosis of single viral particles and other micro-organisms previously localized and visualized in the TEM. © 2014 The Society for Applied Microbiology.

  13. Technical assistance for development of thermally conductive nitride filler for epoxy molding compounds

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Ho Jin; Song, Kee Chan; Jung, In Ha

    2005-07-15

    Technical assistance was carried out to develop nitride filler for thermally conductive epoxy molding compounds. Carbothermal reduction method was used to fabricate silicon nitride powder from mixtures of silica and graphite powders. Microstructure and crystal structure were observed by using scanning electron microscopy and x-ray diffraction technique. Thermal properties of epoxy molding compounds containing silicon nitride were measured by using laser flash method. Fabrication process of silicon nitride nanowire was developed and was applied to a patent.

  14. Demonstration of AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors with silicon-oxy-nitride as the gate insulator

    International Nuclear Information System (INIS)

    Balachander, K.; Arulkumaran, S.; Egawa, T.; Sano, Y.; Baskar, K.

    2005-01-01

    AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors (MOSHEMTs) were fabricated with plasma enhanced chemical vapor deposited silicon oxy-nitride (SiON) as an insulating layer. The compositions of SiON thin films were confirmed using X-ray photoelectron spectroscopy. The fabricated MOSHEMTs exhibited a very high saturation current density of 1.1 A/mm coupled with high positive operational gate voltage up to +7 V. The MOSHEMTs also exhibited four orders of low gate leakage current and high forward-on voltage when compared with the conventional HEMTs. The drain current collapse using gate pulse measurements showed only a negligible difference in the saturation current density revealing the drastic improvement in passivation of the surface states due to the high quality of dielectric thin films deposited. Thus, based on the improved direct-current operation, SiON can be considered to be a potential gate oxide comparable with other dielectric insulators

  15. Investigation of deposition characteristics and properties of high-rate deposited silicon nitride films prepared by atmospheric pressure plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Kakiuchi, H.; Nakahama, Y.; Ohmi, H.; Yasutake, K.; Yoshii, K.; Mori, Y.

    2005-01-01

    Silicon nitride (SiN x ) films have been prepared at extremely high deposition rates by the atmospheric pressure plasma chemical vapor deposition (AP-PCVD) technique on Si(001) wafers from gas mixtures containing He, H 2 , SiH 4 and N 2 or NH 3 . A 150 MHz very high frequency (VHF) power supply was used to generate high-density radicals in the atmospheric pressure plasma. Deposition rate, composition and morphology of the SiN x films prepared with various deposition parameters were studied by scanning electron microscopy and Auger electron spectroscopy. Fourier transformation infrared (FTIR) absorption spectroscopy was also used to characterize the structure and the chemical bonding configurations of the films. Furthermore, etching rate with buffered hydrofluoric acid (BHF) solution, refractive index and capacitance-voltage (C-V) characteristics were measured to evaluate the dielectric properties of the films. It was found that effective passivation of dangling bonds and elimination of excessive hydrogen atoms at the film-growing surface seemed to be the most important factor to form SiN x film with a dense Si-N network. The C-V curve of the optimized film showed good interface properties, although further improvement was necessary for use in the industrial metal-insulator-semiconductor (MIS) applications

  16. III-nitride disk-in-nanowire 1.2 μm monolithic diode laser on (001)silicon

    Energy Technology Data Exchange (ETDEWEB)

    Hazari, Arnab; Aiello, Anthony; Bhattacharya, Pallab [Center for Photonics and Multiscale Nanomaterials, Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); Ng, Tien-Khee; Ooi, Boon S. [Division of Computer, Electrical and Mathematical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia)

    2015-11-09

    III-nitride nanowire diode heterostructures with multiple In{sub 0.85}Ga{sub 0.15}N disks and graded InGaN mode confining regions were grown by molecular beam epitaxy on (001)Si substrates. The aerial density of the 60 nm nanowires is ∼3 × 10{sup 10} cm{sup −2}. A radiative recombination lifetime of 1.84 ns in the disks is measured by time-resolved luminescence measurements. Edge-emitting nanowire lasers have been fabricated and characterized. Measured values of J{sub th}, T{sub 0}, and dg/dn in these devices are 1.24 kA/cm{sup 2}, 242 K, and 5.6 × 10{sup −17} cm{sup 2}, respectively. The peak emission is observed at ∼1.2 μm.

  17. Mocvd Growth of Group-III Nitrides on Silicon Carbide: From Thin Films to Atomically Thin Layers

    Science.gov (United States)

    Al Balushi, Zakaria Y.

    Group-III nitride semiconductors (AlN, GaN, InN and their alloys) are considered one of the most important class of materials for electronic and optoelectronic devices. This is not limited to the blue light-emitting diode (LED) used for efficient solid-state lighting, but other applications as well, such as solar cells, radar and a variety of high frequency power electronics, which are all prime examples of the technological importance of nitride based wide bandgap semiconductors in our daily lives. The goal of this dissertation work was to explore and establish new growth schemes to improve the structural and optical properties of thick to atomically thin films of group-III nitrides grown by metalorganic chemical vapor deposition (MOCVD) on SiC substrates for future novel devices. The first research focus of this dissertation was on the growth of indium gallium nitride (InGaN). This wide bandgap semiconductor has attracted much research attention as an active layer in LEDs and recently as an absorber material for solar cells. InGaN has superior material properties for solar cells due to its wavelength absorption tunability that nearly covers the entire solar spectrum. This can be achieved by controlling the indium content in thick grown material. Thick InGaN films are also of interest as strain reducing based layers for deep-green and red light emitters. The growth of thick films of InGaN is, however, hindered by several combined problems. This includes poor incorporation of indium in alloys, high density of structural and morphological defects, as well as challenges associated with the segregation of indium in thick films. Overcoming some of these material challenges is essential in order integrate thick InGaN films into future optoelectronics. Therefore, this dissertation research investigated the growth mechanism of InGaN layers grown in the N-polar direction by MOCVD as a route to improve the structural and optical properties of thick InGaN films. The growth

  18. Optimization of Controllable Factors in the Aluminum Silicon Eutectic Paste and Rear Silicon Nitride Mono-Passivation Layer of PERC Solar Cells

    Science.gov (United States)

    Park, Sungeun; Park, Hyomin; Kim, Dongseop; Yang, JungYup; Lee, Dongho; Kim, Young-Su; Kim, Hyun-Jong; Suh, Dongchul; Min, Byoung Koun; Kim, Kyung Nam; Park, Se Jin; Kim, Donghwan; Lee, Hae-Seok; Nam, Junggyu; Kang, Yoonmook

    2018-05-01

    Passivated emitter and rear contact (PERC) is a promising technology owing to high efficiency can be achieved with p-type wafer and their easily applicable to existing lines. In case of using p-type mono wafer, 0.5-1% efficiency increase is expected with PERC technologies compared to existing Al BSF solar cells, while for multi-wafer solar cells it is 0.5-0.8%. We addressed the optimization of PERC solar cells using the Al paste. The paste was prepared from the aluminum-silicon alloy with eutectic composition to avoid the formation of voids that degrade the open-circuit voltage. The glass frit of the paste was changed to improve adhesion. Scanning electron microscopy revealed voids and local back surface field between the aluminum electrode and silicon base. We confirmed the conditions on the SiNx passivation layer for achieving higher efficiency and better adhesion for long-term stability. The cell characteristics were compared across cells containing different pastes. PERC solar cells with the Al/Si eutectic paste exhibited the efficiency of 19.6%.

  19. Technology for bonding silicon nitride ceramics. Heat treatment technology to improve diffusion bonding strength; Chikka keiso ceramics no setsugo gijutsu. Kakusan setsugo kyodo kaizen no tame no metsushori gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, M.; Shigematsu, K. [National Industrial Research Institute of Nagoya,Nagoya (Japan)

    1999-01-25

    Silicon nitride ceramics is a structural ceramics with excellent high temperature strength and tenacity, being expected of expansion of application as a high temperature material. However, its processibility is poor, and special sintering technique is required to manufacture members of complex shapes. Therefore, development has been made on a technology to manufacture bonded materials with high mechanical strength, by which diffusion bonding in high temperature nitrogen gas and heat treatment are combined, and crystalline structure in the vicinity of bonding interface is controlled. (translated by NEDO)

  20. Study of silicon-silicon nitride interface properties on planar (1 0 0), planar (1 1 1) and textured surfaces using deep-level transient spectroscopy

    International Nuclear Information System (INIS)

    Gong, Chun; Simoen, Eddy; Posthuma, Niels E; Van Kerschaver, Emmanuel; Poortmans, Jef; Mertens, Robert

    2010-01-01

    Deep-level transient spectroscopy (DLTS) has been applied to metal-insulator-semiconductor (MIS) capacitors fabricated on planar (1 0 0), planar (1 1 1) orientations and textured n-type silicon wafers. Low frequency direct plasma-enhanced chemical vapour deposition Si-SiN x interface properties with and without plasma NH 3 pre-treatment, with and without rapid thermal annealing (RTA) have been investigated. It is shown that three different kinds of defect states are identified at the Si-SiN x interface. For the planar (1 0 0) surface, samples with plasma NH 3 pre-treatment plus RTA show the lowest DLTS signals, which suggests the lowest overall interface states density. For planar (1 1 1) Si surfaces, plasma NH 3 pre-treatment and RTA yield a small improvement. With the textured surface, the RTA step improves the surface passivation quality further but no obvious impact is found with plasma NH 3 pre-treatment. Energy-dependent electron capture cross sections were also measured by small-pulse DLTS. The capture cross sections depend strongly on the energy level and decrease towards the conduction band edge.

  1. Polar and Nonpolar Gallium Nitride and Zinc Oxide based thin film heterostructures Integrated with Sapphire and Silicon

    Science.gov (United States)

    Gupta, Pranav

    This dissertation work explores the understanding of the relaxation and integration of polar and non-polar of GaN and ZnO thin films with Sapphire and silicon substrates. Strain management and epitaxial analysis has been performed on wurtzitic GaN(0001) thin films grown on c-Sapphire and wurtzitic non-polar a-plane GaN(11-20) thin films grown on r-plane Sapphire (10-12) by remote plasma atomic nitrogen source assisted UHV Pulsed Laser Deposition process. It has been established that high-quality 2-dimensional c-axis GaN(0001) nucleation layers can be grown on c-Sapphire by PLD process at growth temperatures as low as ˜650°C. Whereas the c-axis GaN on c-sapphire has biaxially negative misfit, the crystalline anisotropy of the a-plane GaN films on r-Sapphire results in compressive and tensile misfits in the two major orthogonal directions. The measured strains have been analyzed in detail by X-ray, Raman spectroscopy and TEM. Strain relaxation in GaN(0001)/Sapphire thin film heterostructure has been explained by the principle of domain matched epitaxial growth in large planar misfit system and has been demonstrated by TEM study. An attempt has been made to qualitatively understand the minimization of free energy of the system from the strain perspective. Analysis has been presented to quantify the strain components responsible for the compressive strain observed in the GaN(0001) thin films on c-axis Sapphire substrates. It was also observed that gallium rich deposition conditions in PLD process lead to smoother nucleation layers because of higher ad-atom mobility of gallium. We demonstrate near strain relaxed epitaxial (0001) GaN thin films grown on (111) Si substrates using TiN as intermediate buffer layer by remote nitrogen plasma assisted UHV pulsed laser deposition (PLD). Because of large misfits between the TiN/GaN and TiN/Si systems the TIN buffer layer growth occurs via nucleation of interfacial dislocations under domain matching epitaxy paradigm. X-ray and

  2. Chlorine poisoning

    Science.gov (United States)

    ... gas) Gas released when opening a partially filled industrial container of chlorine tablets that have been sitting ... change in acid level of the blood (pH balance), which leads to damage in all of the ...

  3. Experimental and theoretical rationalization of the growth mechanism of silicon quantum dots in non-stoichiometric SiN x : role of chlorine in plasma enhanced chemical vapour deposition.

    Science.gov (United States)

    Mon-Pérez, E; Salazar, J; Ramos, E; Salazar, J Santoyo; Suárez, A López; Dutt, A; Santana, G; Monroy, B Marel

    2016-11-11

    Silicon quantum dots (Si-QDs) embedded in an insulator matrix are important from a technological and application point of view. Thus, being able to synthesize them in situ during the matrix growth process is technologically advantageous. The use of SiH 2 Cl 2 as the silicon precursor in the plasma enhanced chemical vapour deposition (PECVD) process allows us to obtain Si-QDs without post-thermal annealing. Foremost in this work, is a theoretical rationalization of the mechanism responsible for Si-QD generation in a film including an analysis of the energy released by the extraction of HCl and the insertion of silylene species into the terminal surface bonds. From the results obtained using density functional theory (DFT), we propose an explanation of the mechanism responsible for the formation of Si-QDs in non-stoichiometric SiN x starting from chlorinated precursors in a PECVD system. Micrograph images obtained through transmission electron microscopy confirmed the presence of Si-QDs, even in nitrogen-rich (N-rich) samples. The film stoichiometry was controlled by varying the growth parameters, in particular the NH 3 /SiH 2 Cl 2 ratio and hydrogen dilution. Experimental and theoretical results together show that using a PECVD system, along with chlorinated precursors it is possible to obtain Si-QDs at a low substrate temperature without annealing treatment. The optical property studies carried out in the present work highlight the prospects of these thin films for down shifting and as an antireflection coating in silicon solar cells.

  4. Experimental and theoretical rationalization of the growth mechanism of silicon quantum dots in non-stoichiometric SiN x : role of chlorine in plasma enhanced chemical vapour deposition

    Science.gov (United States)

    Mon-Pérez, E.; Salazar, J.; Ramos, E.; Santoyo Salazar, J.; López Suárez, A.; Dutt, A.; Santana, G.; Marel Monroy, B.

    2016-11-01

    Silicon quantum dots (Si-QDs) embedded in an insulator matrix are important from a technological and application point of view. Thus, being able to synthesize them in situ during the matrix growth process is technologically advantageous. The use of SiH2Cl2 as the silicon precursor in the plasma enhanced chemical vapour deposition (PECVD) process allows us to obtain Si-QDs without post-thermal annealing. Foremost in this work, is a theoretical rationalization of the mechanism responsible for Si-QD generation in a film including an analysis of the energy released by the extraction of HCl and the insertion of silylene species into the terminal surface bonds. From the results obtained using density functional theory (DFT), we propose an explanation of the mechanism responsible for the formation of Si-QDs in non-stoichiometric SiN x starting from chlorinated precursors in a PECVD system. Micrograph images obtained through transmission electron microscopy confirmed the presence of Si-QDs, even in nitrogen-rich (N-rich) samples. The film stoichiometry was controlled by varying the growth parameters, in particular the NH3/SiH2Cl2 ratio and hydrogen dilution. Experimental and theoretical results together show that using a PECVD system, along with chlorinated precursors it is possible to obtain Si-QDs at a low substrate temperature without annealing treatment. The optical property studies carried out in the present work highlight the prospects of these thin films for down shifting and as an antireflection coating in silicon solar cells.

  5. Transformation-Toughened Silicon Nitride

    Science.gov (United States)

    1988-08-01

    of pores, could be eliminated by iso - statically pressing the green flexure test bars after the burnout operation and before the sintering...Company Fourth and Canal Streets PO Box 27003 Richmond, VA 23261 Stephen C. Danforth Rutgers University Post Office Box 909 Bowser Road

  6. Oxide-nitride-oxide dielectric stacks with Si nanoparticles obtained by low-energy ion beam synthesis

    International Nuclear Information System (INIS)

    Ioannou-Sougleridis, V; Dimitrakis, P; Vamvakas, V Em; Normand, P; Bonafos, C; Schamm, S; Mouti, A; Assayag, G Ben; Paillard, V

    2007-01-01

    Formation of a thin band of silicon nanoparticles within silicon nitride films by low-energy (1 keV) silicon ion implantation and subsequent thermal annealing is demonstrated. Electrical characterization of metal-insulator-semiconductor capacitors reveals that oxide/Si-nanoparticles-nitride/oxide dielectric stacks exhibit enhanced charge transfer characteristics between the substrate and the silicon nitride layer compared to dielectric stacks using unimplanted silicon nitride. Attractive results are obtained in terms of write/erase memory characteristics and data retention, indicating the large potential of the low-energy ion-beam-synthesis technique in SONOS memory technology

  7. Superplastic forging nitride ceramics

    Science.gov (United States)

    Panda, P.C.; Seydel, E.R.; Raj, R.

    1988-03-22

    A process is disclosed for preparing silicon nitride ceramic parts which are relatively flaw free and which need little or no machining, said process comprising the steps of: (a) preparing a starting powder by wet or dry mixing ingredients comprising by weight from about 70% to about 99% silicon nitride, from about 1% to about 30% of liquid phase forming additive and from 1% to about 7% free silicon; (b) cold pressing to obtain a preform of green density ranging from about 30% to about 75% of theoretical density; (c) sintering at atmospheric pressure in a nitrogen atmosphere at a temperature ranging from about 1,400 C to about 2,200 C to obtain a density which ranges from about 50% to about 100% of theoretical density and which is higher than said preform green density, and (d) press forging workpiece resulting from step (c) by isothermally uniaxially pressing said workpiece in an open die without initial contact between said workpiece and die wall perpendicular to the direction of pressing and so that pressed workpiece does not contact die wall perpendicular to the direction of pressing, to substantially final shape in a nitrogen atmosphere utilizing a temperature within the range of from about 1,400 C to essentially 1,750 C and strain rate within the range of about 10[sup [minus]7] to about 10[sup [minus]1] seconds[sup [minus]1], the temperature and strain rate being such that surface cracks do not occur, said pressing being carried out to obtain a shear deformation greater than 30% whereby superplastic forging is effected.

  8. Alkaline earth metal, silicon, chlorine, hydrogen. A reaction system for the heterogeneous hydrodehalogenation of silicon tetrachloride to nanocrystalline silicon; Erdalkalimetall-Silicium-Chlor-Wasserstoff. Das Reaktionssystem fuer die heterogene Hydrodehalogenierung von Siliciumtetrachlorid bis zum nanokristallinen Silicium

    Energy Technology Data Exchange (ETDEWEB)

    Fiedler, Katja

    2012-02-17

    Reactions of an alkaline earth metal with a SiCl{sub 4}-H{sub 2} result in a quaternary system with a metastable quaternary phase which separates into the metal chloride and nanocrystalline silicon upon cooling. The present study was dedicated to a making a detailed characterisation of the quaternary phase. For this purpose the properties of the quaternary system were derived from those of the six binary and four ternary systems. The first ever characterisation of the surface by means of photoelectron spectroscopy was undertaken. It also proved possible for the first time to follow the formation reaction by measuring the potential difference across the reaction system. Using the results of the characterisation the author presents first steps towards identifying the formation mechanism involved. [German] Im quaternaeren System Erdalkalimetall-Silicium-Chlor-Wasserstoff bildet sich bei der Umsetzung des Metalls mit einer SiCl{sub 4}-H{sub 2}-Atmosphaere eine quaternaere Phase. Diese metastabile Phase zerfaellt beim Abkuehlen in das Metallchlorid und Silicium in nanokristalliner Form. Die vorliegende Arbeit hat sich mit der tiefergehenden Charakterisierung der quaternaeren Phase beschaeftigt. Dazu wurden die Eigenschaften des quaternaeren Systems aus den Eigenschaften der sechs binaeren und vier ternaeren Systemen abgeleitet. Die Oberflaeche wurde erstmals mit Photoelektronenspektroskopie charakterisiert. Zusaetzlich gelang erstmalig die Verfolgung der Bildungsreaktion durch Messung des Spannungsabfalls ueber das Reaktionssystem. Erste Ansaetze zur Aufklaerung des Bildungsmechanismus ausgehend von den Ergebnissen der Charakterisierung wurden zusaetzlich aufgezeigt.

  9. Plasma nitriding of steels

    CERN Document Server

    Aghajani, Hossein

    2017-01-01

    This book focuses on the effect of plasma nitriding on the properties of steels. Parameters of different grades of steels are considered, such as structural and constructional steels, stainless steels and tools steels. The reader will find within the text an introduction to nitriding treatment, the basis of plasma and its roll in nitriding. The authors also address the advantages and disadvantages of plasma nitriding in comparison with other nitriding methods. .

  10. Hydrogen effects in hydrofluorocarbon plasma etching of silicon nitride: Beam study with CF{sup +}, CF{sub 2}{sup +}, CHF{sub 2}{sup +}, and CH{sub 2}F{sup +} ions

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Tomoko; Karahashi, Kazuhiro; Fukasawa, Masanaga; Tatsumi, Tetsuya; Hamaguchi, Satoshi [Center for Atomic and Molecular Technologies, Osaka University, Osaka 565-0871 (Japan); Semiconductor Technology Development Division, SBG, CPDG, Sony Corporation, Atsugi, Kanagawa 243-0014 (Japan); Center for Atomic and Molecular Technologies, Osaka University, Osaka 565-0871 (Japan)

    2011-09-15

    Hydrogen in hydrofluorocarbon plasmas plays an important role in silicon nitride (Si{sub 3}N{sub 4}) reactive ion etching. This study focuses on the elementary reactions of energetic CHF{sub 2}{sup +} and CH{sub 2}F{sup +} ions with Si{sub 3}N{sub 4} surfaces. In the experiments, Si{sub 3}N{sub 4} surfaces were irradiated by monoenergetic (500-1500 eV) beams of CHF{sub 2}{sup +} and CH{sub 2}F{sup +} ions as well as hydrogen-free CF{sub 2}{sup +} and CF{sup +} ions generated by a mass-selected ion beam system and their etching yields and surface properties were examined. It has been found that, when etching takes place, the etching rates of Si{sub 3}N{sub 4} by hydrofluorocarbon ions, i.e., CHF{sub 2}{sup +} and CH{sub 2}F{sup +}, are higher than those by the corresponding fluorocarbon ions, i.e., CF{sub 2}{sup +} and CF{sup +}, respectively. When carbon film deposition takes place, it has been found that hydrogen of incident hydrofluorocarbon ions tends to scavenge fluorine of the deposited film, reducing its fluorine content.

  11. Microfabrication, separations, and detection by mass spectrometry on ultrathin-layer chromatography plates prepared via the low-pressure chemical vapor deposition of silicon nitride onto carbon nanotube templates.

    Science.gov (United States)

    Kanyal, Supriya S; Häbe, Tim T; Cushman, Cody V; Dhunna, Manan; Roychowdhury, Tuhin; Farnsworth, Paul B; Morlock, Gertrud E; Linford, Matthew R

    2015-07-24

    Microfabrication of ultrathin-layer chromatography (UTLC) plates via conformal deposition of silicon nitride by low-pressure chemical vapor deposition onto patterned carbon nanotube (CNT) scaffolds was demonstrated. After removal of the CNTs and hydroxylation, the resulting UTLC phase showed no expansion or distortion of their microfeatures and the absence/reduction of remaining nitrogenic species. Developing time of a mixture of lipophilic dyes on this UTLC plates was 86% shorter than on high-performance thin-layer chromatography (HPTLC) plates. A water-soluble food dye mixture was also separated resulting in low band broadening and reduced developing time compared to HPTLC. For the latter example, mobile phase optimization on a single UTLC plate consisted of 14 developments with different mobile phases, each preceded by a plate prewashing step. The same plate was again reused for additional 11 separations under varying conditions resulting in a development procedure with a mean separation efficiency of 233,000theoretical plates/m and a reduced mobile phase consumption of only 400μL. This repeated use proved the physical robustness of the ultrathin layer and its resistance to damage. The layer was highly suited for hyphenation to ambient mass spectrometry, including desorption electrospray ionization (DESI) mass spectrometry imaging and direct analysis in real time (DART) mass spectrometry. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Chlorine in the stratosphere

    OpenAIRE

    VON CLARMANN, T.

    2013-01-01

    This paper reviews the various aspects of chlorine compounds in the stratosphere, both their roles as reactants and as tracers of dynamical processes. In the stratosphere, reactive chlorine is released from chlorofluorocarbons and other chlorine-containing organic source gases. To a large extent reactive chlorine is then sequestered in reservoir species ClONO2 and HCl. Re-activation of chlorine happens predominantly in polar winter vortices by heterogeneous reaction in combination with sunlig...

  13. Characterization of silicon oxynitride films prepared by the simultaneous implantation of oxygen and nitrogen ions into silicon

    International Nuclear Information System (INIS)

    Hezel, R.; Streb, W.

    1985-01-01

    Silicon oxynitride films about 5 nm in thickness were prepared by simultaneously implanting 5 keV oxygen and nitrogen ions into silicon at room temperature up to saturation. These films with concentrations ranging from pure silicon oxide to silicon nitride were characterized using Auger electron spectroscopy, electron energy loss spectroscopy and depth-concentration profiling. The different behaviour of the silicon oxynitride films compared with those of silicon oxide and silicon nitride with regard to thermal stability and hardness against electron and argon ion irradiation is pointed out. (Auth.)

  14. Small signal modulation characteristics of red-emitting (λ = 610 nm) III-nitride nanowire array lasers on (001) silicon

    KAUST Repository

    Jahangir, Shafat; Frost, Thomas; Hazari, Arnab; Yan, Lifan; Stark, Ethan; LaMountain, Trevor; Millunchick, Joanna M.; Ooi, Boon S.; Bhattacharya, Pallab

    2015-01-01

    The small signal modulation characteristics of an InGaN/GaN nanowire array edge- emitting laser on (001) silicon are reported. The emission wavelength is 610 nm. Lattice matched InAlN cladding layers were incorporated in the laser heterostructure for better mode confinement. The suitability of the nanowire lasers for use in plastic fiber communication systems with direct modulation is demonstrated through their modulation bandwidth of f-3dB,max = 3.1 GHz, very low values of chirp (0.8 Å) and α-parameter, and large differential gain (3.1 × 10-17 cm2).

  15. Small signal modulation characteristics of red-emitting (λ = 610 nm) III-nitride nanowire array lasers on (001) silicon

    KAUST Repository

    Jahangir, Shafat

    2015-02-16

    The small signal modulation characteristics of an InGaN/GaN nanowire array edge- emitting laser on (001) silicon are reported. The emission wavelength is 610 nm. Lattice matched InAlN cladding layers were incorporated in the laser heterostructure for better mode confinement. The suitability of the nanowire lasers for use in plastic fiber communication systems with direct modulation is demonstrated through their modulation bandwidth of f-3dB,max = 3.1 GHz, very low values of chirp (0.8 Å) and α-parameter, and large differential gain (3.1 × 10-17 cm2).

  16. Features of copper etching in chlorine-argon plasma

    International Nuclear Information System (INIS)

    Efremov, A.M.; Svettsov, V.I.

    1995-01-01

    Chlorine mixtures with inert gases including argon exhibit promise as plasma feed gases for etching metals and semiconductors in the microelectronics industry. It was shown that even strong dilution of reactive gas with an inert gas (up to 80-90% of the latter) has virtually no effect in decreasing the rate of plasma etching of materials such as silicon and gallium arsenide, compared to etching in pure chlorine. The principal reactive species responsible for etching these substrates are chlorine atoms therefore, a possible explanation of the effect is an increase in the rate of bulk generation of chlorine atoms in the presence of argon. In this work the authors studied the influence of argon on the rate of copper etching in chlorine, because copper, unlike the above substrates, reacts effectively not only with the atoms but with the ground-state molecules of chlorine

  17. Corrosion resistance of ceramic materials in pyrochemical reprocessing atmosphere by using molten salt for spent nuclear oxide fuel. Corrosion research under chlorine gas condition

    International Nuclear Information System (INIS)

    Takeuchi, Masayuki; Hanada, Keiji; Koizumi, Tsutomu; Aose, Shinichi; Kato, Toshihiro

    2002-12-01

    Pyrochemical reprocessing using molten salts (RIAR process) has been recently developed for spent nuclear oxide fuel and discussed in feasibility study. It is required to improve the corrosion resistance of equipments such as electrolyzer because the process is operated in severe corrosion environment. In this study, the corrosion resistance of ceramic materials was discussed through the thermodynamic calculation and corrosion test. The corrosion test was basically carried out in alkali molten salt under chlorine gas condition. And further consideration about the effects of oxygen, carbon and main fission product's chlorides were evaluated in molten salt. The result of thermodynamic calculation shows most of ceramic oxides have good chemical stability on chlorine, oxygen and uranyl chloride, however the standard Gibb's free energies with carbon have negative value. On the other hand, eleven kinds of ceramic materials were examined by corrosion test, then silicon nitride, mullite and cordierite have a good corrosion resistance less than 0.1 mm/y. Cracks were not observed on the materials and flexural strength did not reduce remarkably after 480 hours test in molten salt with Cl 2 -O 2 bubbling. In conclusion, these three ceramic materials are most applicable materials for the pyrochemical reprocessing process with chlorine gas condition. (author)

  18. Preparation of uranium nitride

    International Nuclear Information System (INIS)

    Potter, R.A.; Tennery, V.J.

    1976-01-01

    A process is described for preparing actinide-nitrides from massive actinide metal which is suitable for sintering into low density fuel shapes by partially hydriding the massive metal and simultaneously dehydriding and nitriding the dehydrided portion. The process is repeated until all of the massive metal is converted to a nitride

  19. Deposition of thin layers of boron nitrides and hydrogenated microcrystalline silicon assisted by high current direct current arc plasma; Deposition assistee par un plasma a arc a haut courant continu de couches minces de Nitrure de Bore et de Silicium microcristallin hydrogene

    Energy Technology Data Exchange (ETDEWEB)

    Franz, D. [Ecole Polytechnique Federale de Lausanne, Centre de Recherches en Physique des Plasmas (CRPP), CH-1015 Lausanne (Switzerland)

    1999-09-01

    In the frame of this thesis, a high current direct current arc (HCDCA) used for the industrial deposition of diamond, has been adapted to study the deposition of two types of coatings: a) boron nitride, whose cubic phase is similar to diamond, for tribological applications, b) hydrogenated microcrystalline silicon, for applications in the semiconductor fields (flat panel displays, solar cells,...). For the deposition of these coatings, the substrates were placed in the diffusion region of the arc. The substrate heating is mainly due to atomic species recombining on its surface. The deposition temperature, varying from 300 to 900 {sup o}C according to the films deposited, is determined by the substrate position, the arc power and the injected gas fluxes, without the use of any external heating or cooling system. Measurements performed on the arc plasma show that the electronic temperature is around 2 eV (23'000 K) while the gas temperature is lower than 5500 K. Typical electronic densities are in the range of 10{sup 12}-10{sup 1'}3 cm{sup -3}. For the deposition of boron nitride films, different boron precursors were used and a wide parameter range was investigated. The extreme difficulty of synthesising cubic boron nitride films by chemical vapour deposition (CVD) did not allow to stabilize the cubic phase of boron nitride in HCDCA. Coatings resulted in hexagonal or amorphous boron nitride with a chemical composition close to stoichiometric. The presence of hydrogen leads to the deposition of rough and porous films. Negative biasing of the samples, for positive ion bombardment, is commonly used to stabilize the cubic phase. In HCDCA and in our biasing range, only a densification of the films could be observed. A boron nitride deposition plasma study by infrared absorption spectroscopy in a capacitive radio frequency reactor has demonstrated the usefulness of this diagnostic for the understanding of the various chemical reactions which occur in this kind

  20. Contact pin-printing of albumin-fungicide conjugate for silicon nitride-based sensors biofunctionalization: Multi-technique surface analysis for optimum immunoassay performance

    Science.gov (United States)

    Gajos, Katarzyna; Budkowski, Andrzej; Tsialla, Zoi; Petrou, Panagiota; Awsiuk, Kamil; Dąbczyński, Paweł; Bernasik, Andrzej; Rysz, Jakub; Misiakos, Konstantinos; Raptis, Ioannis; Kakabakos, Sotirios

    2017-07-01

    Mass fabrication of integrated biosensors on silicon chips is facilitated by contact pin-printing, applied for biofunctionalization of individual Si3N4-based transducers at wafer-scale. To optimize the biofunctionalization for immunochemical (competitive) detection of fungicide thiabendazole (TBZ), Si3N4 surfaces are modified with (3-aminopropyl)triethoxysilane and examined after: immobilization of BSA-TBZ conjugate (probe) from solutions with different concentration, blocking with bovine serum albumin (BSA), and immunoreaction with a mouse monoclonal antibody against TBZ. Nanostructure, surface density, probe composition and coverage uniformity of protein layers are evaluated with Atomic Force Microscopy, Spectroscopic Ellipsometry, Time-of-Flight Secondary Ion Mass Spectrometry and X-ray Photoelectron Spectroscopy. Contact pin-printing of overlapping probe spots is compared with hand spotted areas. Contact pin-printing resulted in two-fold increase of immobilized probe surface density as compared to hand spotting. Regarding BSA-TBZ immobilization, an incomplete monolayer develops into a bilayer as the concentration of BSA-TBZ molecules in the printing solution increases from 25 to 100 μg/mL. Upon blocking, however, a complete protein monolayer is formed for all the BSA-TBZ concentrations used. Free surface sites are filled with BSA for low surface coverage with BSA-TBZ, whereas loosely bound BSA-TBZ molecules are removed from the BSA-TBZ bilayer. As a consequence immunoreaction efficiency increases with the printing probe concentration.

  1. Impact of AlN seeding layer growth rate in MOVPE growth of semi-polar gallium nitride structures on high index silicon

    Energy Technology Data Exchange (ETDEWEB)

    Ravash, Roghaiyeh; Blaesing, Juergen; Hempel, Thomas; Noltemeyer, Martin; Dadgar, Armin; Christen, Juergen; Krost, Alois [Otto-von-Guericke-University Magdeburg, FNW/IEP/AHE, Postfach 4120, 39016 Magdeburg (Germany)

    2011-03-15

    We present metal organic vapor phase epitaxy growth of semi-polar GaN structures on high index silicon surfaces. The crystallographic structure of GaN grown on Si(112), (115), and (117) substrates is investigated by X-ray analysis and scanning electron microscopy. X-ray diffraction was performed in Bragg Brentano geometry as well as pole figure measurements. The results demonstrate that the orientation of GaN crystallites on Si is significantly dependent on thickness of the AlN seeding layer and TMAl-flow rate. We observe that the crystallographic structures of GaN by applying thin AlN seeding layers grown with high TMAl-flow rate depend on Si surface direction while they are independent for thicker layers. By applying such seeding layer we obtain single crystalline semi-polar GaN on Si(112), while GaN structures grown with the same growth parameters on Si(117) show four components of GaN(0002). (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Nitrogen ion induced nitridation of Si(111) surface: Energy and fluence dependence

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Praveen [Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064 (India); ISOM, Universidad Politecnia de Madrid, 28040 (Spain); Kumar, Mahesh [Physics and Energy Harvesting Group, National Physical Laboratory, New Delhi 110012 (India); Nötzel, R. [ISOM, Universidad Politecnia de Madrid, 28040 (Spain); Shivaprasad, S.M., E-mail: smsprasad@jncasr.ac.in [Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064 (India)

    2014-06-01

    We present the surface modification of Si(111) into silicon nitride by exposure to energetic N{sub 2}{sup +} ions. In-situ UHV experiments have been performed to optimize the energy and fluence of the N{sub 2}{sup +} ions to form silicon nitride at room temperature (RT) and characterized in-situ by X-ray photoelectron spectroscopy. We have used N{sub 2}{sup +} ion beams in the energy range of 0.2–5.0 keV of different fluence to induce surface reactions, which lead to the formation of Si{sub x}N{sub y} on the Si(111) surface. The XPS core level spectra of Si(2p) and N(1s) have been deconvoluted into different oxidation states to extract qualitative information, while survey scans have been used for quantifying of the silicon nitride formation, valence band spectra show that as the N{sub 2}{sup +} ion fluence increases, there is an increase in the band gap. The secondary electron emission spectra region of photoemission is used to evaluate the change in the work function during the nitridation process. The results show that surface nitridation initially increases rapidly with ion fluence and then saturates. - Highlights: • A systematic study for the formation of silicon nitride on Si(111). • Investigation of optimal energy and fluence for energetic N{sub 2}{sup +} ions. • Silicon nitride formation at room temperature on Si(111)

  3. Contact pin-printing of albumin-fungicide conjugate for silicon nitride-based sensors biofunctionalization: Multi-technique surface analysis for optimum immunoassay performance

    Energy Technology Data Exchange (ETDEWEB)

    Gajos, Katarzyna, E-mail: katarzyna.gajos@doctoral.uj.edu.pl [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza, 11, 30-348 Kraków (Poland); Budkowski, Andrzej [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza, 11, 30-348 Kraków (Poland); Tsialla, Zoi; Petrou, Panagiota [Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, NCSR Demokritos, P. Grigoriou & Neapoleos St., Aghia Paraksevi 15310, Athens (Greece); Awsiuk, Kamil; Dąbczyński, Paweł [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza, 11, 30-348 Kraków (Poland); Bernasik, Andrzej [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Mickiewicza 30, 30-059 Kraków (Poland); Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Mickiewicza 30, 30-059 Kraków (Poland); Rysz, Jakub [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza, 11, 30-348 Kraków (Poland); Misiakos, Konstantinos; Raptis, Ioannis [Department of Microelectronics, Institute of Nanoscience and Nanotechnology, NCSR Demokritos, P. Grigoriou & Neapoleos St., Aghia Paraksevi 15310, Athens (Greece); Kakabakos, Sotirios [Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, NCSR Demokritos, P. Grigoriou & Neapoleos St., Aghia Paraksevi 15310, Athens (Greece)

    2017-07-15

    Highlights: • Contact pin-printing of overlapping probe spots and spotting by hand are compared. • Contact pin-printing favors probe immobilization with two-fold higher surface density. • Incomplete monolayer develops to bilayer as printing solution concentration increases. • Blocking molecules complete probe monolayer but reduce probe bilayer. • Surface immunoreaction increases with probe concentration in printing solution. - Abstract: Mass fabrication of integrated biosensors on silicon chips is facilitated by contact pin-printing, applied for biofunctionalization of individual Si{sub 3}N{sub 4}-based transducers at wafer-scale. To optimize the biofunctionalization for immunochemical (competitive) detection of fungicide thiabendazole (TBZ), Si{sub 3}N{sub 4} surfaces are modified with (3-aminopropyl)triethoxysilane and examined after: immobilization of BSA-TBZ conjugate (probe) from solutions with different concentration, blocking with bovine serum albumin (BSA), and immunoreaction with a mouse monoclonal antibody against TBZ. Nanostructure, surface density, probe composition and coverage uniformity of protein layers are evaluated with Atomic Force Microscopy, Spectroscopic Ellipsometry, Time-of-Flight Secondary Ion Mass Spectrometry and X-ray Photoelectron Spectroscopy. Contact pin-printing of overlapping probe spots is compared with hand spotted areas. Contact pin-printing resulted in two-fold increase of immobilized probe surface density as compared to hand spotting. Regarding BSA-TBZ immobilization, an incomplete monolayer develops into a bilayer as the concentration of BSA-TBZ molecules in the printing solution increases from 25 to 100 μg/mL. Upon blocking, however, a complete protein monolayer is formed for all the BSA-TBZ concentrations used. Free surface sites are filled with BSA for low surface coverage with BSA-TBZ, whereas loosely bound BSA-TBZ molecules are removed from the BSA-TBZ bilayer. As a consequence immunoreaction efficiency

  4. Technology assessment: Chlorine chemistry

    International Nuclear Information System (INIS)

    Wolff, H.; Alwast, H.; Buttgereit, R.

    1994-01-01

    Chlorine is not just one of many chemical feedstocks which is used in a few definitely harmful products like PVC or CFC but is irrelevant in all other respects. Just the opposite is true: There is hardly any product line of the chemical industry that can do without chlorine, from herbicides and pesticides to dyes, plastics, pharmaceuticals, photographic atricles, and cosmetics. Chlorine is not only a key element of chemical production but also an ubiquitous element of everyday life in civilisation. There are even many who would agree that the volume of chlorine production is an indicator of the competitive strength and national wealth of a modern society. By now, however, it has become evident that the unreflected use of chlorine is no longer ecologically acceptable. The consequences of a chlorine phase-out as compared to the continued chlorine production at the present level were investigated scientifically by a PROGNOS team. They are presented in this book. (orig.) [de

  5. Growth of gallium nitride based devices on silicon(001) substrates by metalorganic vapor phase epitaxy; Wachstum von Galliumnitrid-basierten Bauelementen auf Silizium(001)-Substraten mittels metallorganischer Gasphasenepitaxie

    Energy Technology Data Exchange (ETDEWEB)

    Reiher, Fabian

    2009-02-25

    The main topic of this thesis is to investigate GaN-based layer systems grown by metalorganic vapor phase epitaxy on Si(001) substrates. A temperature shift up to 45 K is measured for a complete device structure on a 2-inch silicon substrate. By using a 40 nm thin LT-AlN-seed layer (680 C), the GaN crystallites on Si(001) substrates are almost oriented with their GaN(10 anti 12)-planes parallel to the Si(001)-plane. A four-fold azimuthal symmetry occurs for these layers, with the GaN[10 anti 11]-direction is aligned parallel to one of the four equivalent left angle 110 right angle -directions, respectively. However, a mono-crystalline and fully coalesced GaN-layer with this crystallographic orientation could not yet been obtained. If a deposition temperature of more than 1100 C is used for the AlN-seed layer, solely the GaN[0001]- growth direction of crystallites occurs in the main GaN layer on Si(001) substrates. These c-axis oriented GaN columns feature two opposite azimuthal alignments that are rotated by 90 with respect to each other and with GaN[11 anti 20] parallel Si[110] and GaN[10 anti 10] parallel Si[110], respectively. By using 4 off-oriented substrates towards the Si[110]-direction, one certain azimuthal texture component can be selected. The critical value of the miscut angle corresponds to theoretical calculations predicting the occurrence of atomic double steps on the Si(001) surface. The achieved crystallographic quality of the GaN layers on Si(001) is characterized by having a tilt of FWHM=0.27 and a twist of FWHM=0.8 of the crystallites, determined by X-ray diffraction. A completely crack-free, up to 2.5 {mu}m thick, and mono-crystalline GaN-template can be realized on Si(001), integrating 4 or 5 LT-AlN-interlayers in the GaN buffer structure. Based on this structure, the first successful implementation of an (InGaN/GaN)-LED on Si(001) is achieved. Furthermore, the possible fabrication of GaN-based FET-structures is demonstrated with a fully

  6. Gold film with gold nitride - A conductor but harder than gold

    International Nuclear Information System (INIS)

    Siller, L.; Peltekis, N.; Krishnamurthy, S.; Chao, Y.; Bull, S.J.; Hunt, M.R.C.

    2005-01-01

    The formation of surface nitrides on gold films is a particularly attractive proposition, addressing the need to produce harder, but still conductive, gold coatings which reduce wear but avoid the pollution associated with conventional additives. Here we report production of large area gold nitride films on silicon substrates, using reactive ion sputtering and plasma etching, without the need for ultrahigh vacuum. Nanoindentation data show that gold nitride films have a hardness ∼50% greater than that of pure gold. These results are important for large-scale applications of gold nitride in coatings and electronics

  7. Fundamental characterization of the effect of nitride sidewall spacer process on boron dose loss in ultra-shallow junction formation

    Energy Technology Data Exchange (ETDEWEB)

    Kohli, P. [Silicon Technology Development, Texas Instruments, Dallas, TX 75243 (United States) and Microelectronics Research Center, University of Texas, Austin, TX 78758 (United States)]. E-mail: puneet.kohli@sematech.org; Chakravarthi, S. [Silicon Technology Development, Texas Instruments, Dallas, TX 75243 (United States); Jain, Amitabh [Silicon Technology Development, Texas Instruments, Dallas, TX 75243 (United States); Bu, H. [Silicon Technology Development, Texas Instruments, Dallas, TX 75243 (United States); Mehrotra, M. [Silicon Technology Development, Texas Instruments, Dallas, TX 75243 (United States); Dunham, S.T. [Department of Electrical Engineering, University of Washington, Seattle, WA 98195 (United States); Banerjee, S.K. [Microelectronics Research Center, University of Texas, Austin, TX 78758 (United States)

    2004-12-15

    A nitride spacer with an underlying deposited tetraethoxysilane (TEOS) oxide that behaves as a convenient etch stop layer is a popular choice for sidewall spacer in modern complementary metal oxide semiconductor (CMOS) process flows. In this work, we have investigated the effect of the silicon nitride spacer process chemistry on the boron profile in silicon and the related dose loss of B from Si into silicon dioxide. This is reflected as a dramatic change in the junction depth, junction abruptness and junction peak concentration for the different nitride chemistries. We conclude that the silicon nitride influences the concentration of hydrogen in the silicon dioxide and different nitride chemistries result in different concentrations of hydrogen in the silicon dioxide during the final source/drain anneal. The presence of H enhances the diffusivity of B in the silicon dioxide and thereby results in a significant dose loss from the Si into the silicon dioxide. In this work, we show that this dose loss can be minimized and the junction profile engineered by choosing a desirable nitride chemistry.

  8. Alternative methods for chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Fiessinger, F; Rook, J J; Duguet, J P

    1985-12-01

    Existing disinfectants are oxidative agents which all present negative effects on subsequent treatment processes. None of them has decisive advantages over chlorine, although chlorine-dioxide and chloramines might at times be preferable. Optimum treatment practices will improve the removal of organic precursors before final disinfection which could then consist in a light chlorine addition. A philosophy of radical change in water treatment technology encompassing physical treatment without chemicals such as membrane filtration, solid disinfectants is presented.

  9. Chlorination and chloramines formation

    International Nuclear Information System (INIS)

    Yee, Lim Fang; Mohd Pauzi Abdullah; Sadia Ata; Abbas Abdullah; Basar IShak; Khairul Nidzham

    2008-01-01

    Chlorination is the most important method of disinfection in Malaysia which aims at ensuring an acceptable and safe drinking water quality. The dosing of chlorine to surface water containing ammonia and nitrogen compounds may form chloramines in the treated water. During this reaction, inorganic and organic chloramines are formed. The recommended maximum acceptable concentration (MAC) for chloramines in drinking water is 3000 μg/L. The production of monochloramine, dichloramine and trichloramine is highly dependent upon pH, contact time and the chlorine to ammonia molar ratio. The purpose of this study is to examine the formation of chloramines that occur upon the chlorination during the treatment process. Chloramines were determined using the N,N-diethyl-p-phenylenediamine (DPD) colorimetric method. The influences of ammonia, pH and chlorine dosage on the chloramines formation were also studied. This paper presents a modeling approach based on regression analysis which is designed to estimate the formation of chloramines. The correlation between the concentration of chloramines and the ammonia, pH and chlorine dosage was examined. In all cases, the quantity of chloramines formed depended linearly upon the amount of chlorine dosage. On the basis of this study it reveals that the concentration of chloramines is a function of chlorine dosage and the ammonia concentration to the chlorination process. PH seems to not significantly affect the formation of chloramines. (author)

  10. Electrochemical properties of lanthanum nitride with calcium nitride additions

    International Nuclear Information System (INIS)

    Lesunova, R.P.; Fishman, L.S.

    1986-01-01

    This paper reports on the electrochemical properties of lanthanum nitride with calcium nitride added. The lanthanum nitride was obtained by nitriding metallic lanthanum at 870 K in an ammonia stream. The product contained Cl, Pr, Nd, Sm, Fe, Ca, Cu, Mo, Mg, Al, Si, and Be. The calcium nitride was obtained by nitriding metallic calcium in a nitrogen stream. The conductivity on the LaN/C 3 N 2 system components are shown as a function of temperature. A table shows the solid solutions to be virtually electronic conductors and the lanthanum nitride a mixed conductor

  11. High efficiency nitride based phosphores for white LEDs

    NARCIS (Netherlands)

    Li, Yuan Qiang; Hintzen, H.T.J.M.

    2008-01-01

    In this overview paper, novel rare-earth doped silicon nitride based phosphors for white LEDs applications have been demonstrated. The luminescence properties of orange-red-emitting phosphors (M2Si5N8:Eu2+) and green-to-yellow emitting phosphors (MSi2N2O2:Eu2+, M = Ca, Sr, Ba) are discussed in

  12. Effect of microstructure on the high temperature strength of nitride

    Indian Academy of Sciences (India)

    Effect of microstructure on the high temperature strength of nitride bonded silicon carbide composite. J Rakshit P K Das. Composites Volume ... The effect of these parameters on room temperature and high temperature strength of the composite up to 1300°C in ambient condition were studied. The high temperature flexural ...

  13. Superconducting structure with layers of niobium nitride and aluminum nitride

    International Nuclear Information System (INIS)

    Murduck, J.M.; Lepetre, Y.J.; Schuller, I.K.; Ketterson, J.B.

    1989-01-01

    A superconducting structure is formed by depositing alternate layers of aluminum nitride and niobium nitride on a substrate. Deposition methods include dc magnetron reactive sputtering, rf magnetron reactive sputtering, thin-film diffusion, chemical vapor deposition, and ion-beam deposition. Structures have been built with layers of niobium nitride and aluminum nitride having thicknesses in a range of 20 to 350 Angstroms. Best results have been achieved with films of niobium nitride deposited to a thickness of approximately 70 Angstroms and aluminum nitride deposited to a thickness of approximately 20 Angstroms. Such films of niobium nitride separated by a single layer of aluminum nitride are useful in forming Josephson junctions. Structures of 30 or more alternating layers of niobium nitride and aluminum nitride are useful when deposited on fixed substrates or flexible strips to form bulk superconductors for carrying electric current. They are also adaptable as voltage-controlled microwave energy sources. 8 figs

  14. Chlorine solar neutrino experiment

    International Nuclear Information System (INIS)

    Rowley, J.K.; Cleveland, B.T.; Davis, R. Jr.

    1984-01-01

    The chlorine solar neutrino experiment in the Homestake Gold Mine is described and the results obtained with the chlorine detector over the last fourteen years are summarized and discussed. Background processes producing 37 Ar and the question of the constancy of the production rate of 37 Ar are given special emphasis

  15. Ion beam studied of silicon oxynitride and silicon nitroxide thin layers

    International Nuclear Information System (INIS)

    Oude Elferink, J.B.

    1989-01-01

    In this the processes occurring during high temperature treatments of silicon oxynitride and silicon oxide layers are described. Oxynitride layers with various atomic oxygen to nitrogen concentration ration (O/N) are considered. The high energy ion beam techniques Rutherford backscattering spectroscopy, elastic recoil detection and nuclear reaction analysis have been used to study the layer structures. A detailed discussion of these ion beam techniques is given. Numerical methods used to obtain quantitative data on elemental compositions and depth profiles are described. The electrical compositions and depth profiles are described. The electrical properties of silicon nitride films are known to be influenced by the behaviour of hydrogen in the film during high temperature anneling. Investigations of the behaviour of hydrogen are presented. Oxidation of silicon (oxy)nitride films in O 2 /H 2 0/HCl and nitridation of silicon dioxide films in NH 3 are considered since oxynitrides are applied as an oxidation mask in the LOCOS (Local oxidation of silicon) process. The nitridation of silicon oxide layers in an ammonia ambient is considered. The initial stage and the dependence on the oxide thickness of nitrogen and hydrogen incorporation are discussed. Finally, oxidation of silicon oxynitride layers and of silicon oxide layers are compared. (author). 76 refs.; 48 figs.; 1 tab

  16. Industrial Silicon Wafer Solar Cells

    OpenAIRE

    Neuhaus, Dirk-Holger; Münzer, Adolf

    2007-01-01

    In 2006, around 86% of all wafer-based silicon solar cells were produced using screen printing to form the silver front and aluminium rear contacts and chemical vapour deposition to grow silicon nitride as the antireflection coating onto the front surface. This paper reviews this dominant solar cell technology looking into state-of-the-art equipment and corresponding processes for each process step. The main efficiency losses of this type of solar cell are analyzed to demonstrate the future e...

  17. Ion nitriding of aluminium

    International Nuclear Information System (INIS)

    Fitz, T.

    2002-09-01

    The present study is devoted to the investigation of the mechanism of aluminium nitriding by a technique that employs implantation of low-energy nitrogen ions and diffusional transport of atoms. The nitriding of aluminium is investigated, because this is a method for surface modification of aluminium and has a potential for application in a broad spectrum of fields such as automobile, marine, aviation, space technologies, etc. However, at present nitriding of aluminium does not find any large scale industrial application, due to problems in the formation of stoichiometric aluminium nitride layers with a sufficient thickness and good quality. For the purposes of this study, ion nitriding is chosen, as an ion beam method with the advantage of good and independent control over the process parameters, which thus can be related uniquely to the physical properties of the resulting layers. Moreover, ion nitriding has a close similarity to plasma nitriding and plasma immersion ion implantation, which are methods with a potential for industrial application. (orig.)

  18. Chemical vapor deposition of refractory ternary nitrides for advanced diffusion barriers

    Energy Technology Data Exchange (ETDEWEB)

    Custer, Jonathan S.; Fleming, James G.; Roherty-Osmun, Elizabeth; Smith, Paul Martin

    1998-09-22

    Refractory ternary nitride films for diffusion barriers in microelectronics have been grown using chemical vapor deposition. Thin films of titanium-silicon-nitride, tungsten-boron-nitride, and tungsten-silicon-nitride of various compositions have been deposited on 150 mm Si wafers. The microstructure of the films are either fully amorphous for the tungsten based films, or nauocrystalline TiN in an amorphous matrix for titanium-silicon-nitride. All films exhibit step coverages suitable for use in future microelectronics generations. Selected films have been tested as diffusion barriers between copper and silicon, and generally perform extremely weH. These fiIms are promising candidates for advanced diffusion barriers for microelectronics applications. The manufacturing of silicon wafers into integrated circuits uses many different process and materials. The manufacturing process is usually divided into two parts: the front end of line (FEOL) and the back end of line (BEOL). In the FEOL the individual transistors that are the heart of an integrated circuit are made on the silicon wafer. The responsibility of the BEOL is to wire all the transistors together to make a complete circuit. The transistors are fabricated in the silicon itself. The wiring is made out of metal, currently aluminum and tungsten, insulated by silicon dioxide, see Figure 1. Unfortunately, silicon will diffuse into aluminum, causing aluminum spiking of junctions, killing transistors. Similarly, during chemical vapor deposition (CVD) of tungsten from ~fj, the reactivity of the fluorine can cause "worn-holes" in the silicon, also destroying transistors. The solution to these problems is a so-called diffusion barrier, which will allow current to pass from the transistors to the wiring, but will prevent reactions between silicon and the metal.

  19. Thermal shock investigation of silicon nitride

    International Nuclear Information System (INIS)

    Ziegler, G.; Leucht, R.

    1977-01-01

    In this work, the thermal shock properties of commercial reaction-bonded Si 3 N 4 quality material (RBSN), of commercial hot-pressed Si 3 N 4 (HPSN) and of different laboratory grades of hot-pressed Si 3 N 4 were examined. The thermal shock properties of RBSN quality material differ according to the structure considerably: The critical temperature difference for sample crossections of 5 x 5 or 6 x 6 mm after quenching in oil lies between 730 0 C and over 1400 0 C. The best thermal shock properties are shown by high density RBSN quality material having very fine pores and high initial strength. The results indicate that for RBSN large pores and density inhomogenities are responsible for bad thermal shock properties. Resistance to fast temperature change is higher for hot-pressed Si 3 N 4 than for RBSN quality material. In HPSN, the thermal shock results show dependence on structure. High MgO content and the associated coarse rod-shaped configuration of the β phase and structural inhomogenities affect the thermal shock properties in an adverse way. (orig.) [de

  20. Dispersion toughened silicon carbon ceramics

    Science.gov (United States)

    Wei, G.C.

    1984-01-01

    Fracture resistant silicon carbide ceramics are provided by incorporating therein a particulate dispersoid selected from the group consisting of (a) a mixture of boron, carbon and tungsten, (b) a mixture of boron, carbon and molybdenum, (c) a mixture of boron, carbon and titanium carbide, (d) a mixture of aluminum oxide and zirconium oxide, and (e) boron nitride. 4 figures.

  1. Bond strength tests between silicon wafers and duran tubes (fusion bonded fluidic interconnects)

    NARCIS (Netherlands)

    Fazal, I.; Berenschot, Johan W.; de Boer, J.H.; Jansen, Henricus V.; Elwenspoek, Michael Curt

    2005-01-01

    The fusion bond strength of glass tubes with standard silicon wafers is presented. Experiments with plain silicon wafers and those coated with silicon oxide and silicon nitride are presented. Results obtained are discussed in terms of homogeneity and strength of fusion bond. High pressure testing

  2. Thermodynamic consideration on chlorination of uraniferous phosphorite

    International Nuclear Information System (INIS)

    Itagaki, Kimio; Tozawa, Kazuteru; Taki, Tomihiro; Hirono, Shuichiro.

    1989-01-01

    The uranium ore of low grade which has apatite as a main mineral, but is different from the phosphorite used as the raw material for phosphoric acid production, exists in large amount in South America and Africa continents, and the importance of its effective utilization as future uranium resources is recognized. The Power Reactor and Nuclear Fuel Development Corp. took up the establishment of the treatment techniques to make this ore into resources as the subject of a project, and proposed the process of volatilizing the uranium in the ore as the chloride and recovering it, and at present, it attempts the experiment on the chlorination treatment. In this paper, the thermodynamic examination on the feasibility of this process, the optimum condition for leaving calcium existing in a large amount in the ore as the phosphate without chlorination and recovering only uranium by chlorination and volatilization, the phase reaction equilibrium chart and the calculation method according to thermodynamics concerning the behavior of chlorination of accompanying elements such as iron, silicon and aluminum and the effect of moisture in the ore are reported. (K.I.)

  3. Behaviour of fluoride and dissolved silicon in Gouthami Godavari estuarine environment

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.; Sudhakar, U.; Varaprasad, S.J.D.

    The concentrations of fluoride and dissolved silicon in Gouthami-Godavari estuarine region (Andhra Pradesh, India) have been measured as a function of chlorinity during different seasons. Fluoride and dissolved silicon behave conservatively during...

  4. Analysis of the properties of silicon nitride based ceramic (Si{sub 3}N{sub 4}) cutting tool using different addictive; Analise das propriedades de ferramenta de corte ceramicas de nitreto de silicio (Si{sub 3}N{sub 4}) usando diferentes aditivos

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Joaquim Lopes; Souza, Jose Vitor Candido de; Raymundo, Emerson Augusto [Centro Universitario de Volta Redonda (UNIFOA), Volta Redonda, RJ (Brazil); Silva, Oliverio Macedo Moreira [Centro Tecnico Aeroespacial (CTA), Sao Jose dos Campos, SP (Brazil)

    2013-06-15

    The constant search for new materials is part of the scientific and technological development of the industries. Ceramic been presenting important developments in terms of scientific and technological development, highlighting the predominance of covalent ceramics, which has important applications where abrasion resistance and hardness are required. Between covalent materials, several research papers in search of property improvements and cost reduction. However the production of ceramics of silicon nitride (Si{sub 3}N{sub 4}) with a reduced cost is possible only if used methods and different additives. The aim of this work is the development of compositions based on silicon nitride (Si{sub 3}N{sub 4}) using different additives such as Y{sub 2}O{sub 3}, CeO{sub 2}, Al{sub 2}O{sub 3} , and CTR{sub 2}O{sub 3} in varying amounts. For the development of ceramics, the mixtures were homogenized, dried, compacted and sintered using the sintering process of 1850°C for 1 hour, with a heating rate of 25°C/min. The characterizations were performed as a function of relative density by Archimedes method, the mass loss measured before and after sintering, phase analysis by X-ray diffraction, microstructure by scanning electron microscopy (SEM), and hardness and fracture toughness indentation method. The results showed relative density 97-98, Vickers hardness 17-19 GPa, fracture toughness from 5.6 to 6.8 MPa.m{sup 1/2}. The different phases were obtained depending on the types of additives used. The obtained results are promising for tribological applications. (author)

  5. Strengthening of oxidation resistant materials for gas turbine applications. [treatment of silicon ceramics for increased flexural strength and impact resistance

    Science.gov (United States)

    Kirchner, H. P.

    1974-01-01

    Silicon nitride and silicon carbide ceramics were treated to form compressive surface layers. On the silicon carbide, quenching and thermal exposure treatments were used, and on the silicon nitride, quenching, carburizing, and a combination of quenching and carburizing were used. In some cases substantial improvements in impact resistance and/or flexural strength were observed. The presence of compressive surface stresses was demonstrated by slotted rod tests.

  6. The failure of aluminium nitride under shock

    International Nuclear Information System (INIS)

    Pickup, I.M.; Bourne, N.K.

    2002-01-01

    The shear strength of aluminium nitride has been measured over a range of impact stresses by measuring lateral stresses in plate impact experiments. The range of impact stress spanned several key shock thresholds for the material, pre and post Hugoniot elastic limit and up to values where the hexagonal to cubic phase transition starts. The shear strength measurements indicate significant inelastic damage at stress levels in excess of the HEL, but a significant recovery of strength at the highest impact stress was observed. This stress equates to the phase transition stress. The shear strength behaviour is compared to that of silicon carbide, which does not exhibit a phase change at these impact velocities

  7. Silicon nanostructures produced by laser direct etching

    DEFF Research Database (Denmark)

    Müllenborn, Matthias; Dirac, Paul Andreas Holger; Petersen, Jon Wulff

    1995-01-01

    A laser direct-write process has been applied to structure silicon on a nanometer scale. In this process, a silicon substrate, placed in a chlorine ambience, is locally heated above its melting point by a continuous-wave laser and translated by high-resolution direct-current motor stages. Only...

  8. Zirconia concentrate chlorination

    International Nuclear Information System (INIS)

    Costa, N.G.; Albuquerque Brocchi, E. de

    1990-01-01

    Chlorination experiments were conducted in order to study the kinetics of gasification of the zirconium oxide present in the zirconia concentrate. The variables studied are temperature (1173 to 1373 K), percentage of reducing agent (12 to 36%) and porosity (22 to 30%). The results indicated a greater influence of temperature and percentage of reducing agent as well as allowed the conclusion that a balance between the levels of these variables is an important factor in the appropriate chlorination conditions. (author)

  9. Chlorine trifluoride (1963)

    International Nuclear Information System (INIS)

    Vincent, L.M.; Gillardeau, J.

    1963-01-01

    This monograph on chlorine trifluoride may be considered as a working tool useful in gaseous diffusion research. It consists of data gathered from the literature and includes furthermore a certain amount of original data. This monograph groups together the physical, chemical and physiological properties of chlorine trifluoride, as well as the preparation and analytical methods. It has been thought wise to add some technological information, and the safety regulations governing its use. (authors) [fr

  10. AlN powder synthesis via nitriding reaction of aluminum sub-chloride

    Energy Technology Data Exchange (ETDEWEB)

    Ohashi, T.; Nishida, T.; Sugiura, M. (Waseda Univ., Tokyo (Japan). Graduate School); Fuwa, A. (Waseda Univ., Tokyo (Japan))

    1993-06-01

    In order to obtain the pertinent properties of aluminium nitride in its sintered form, it is desirable to have powders of finer sizes with narrower size distribution and higher purity, thereby making the sintering processing easier and the final body denser. Instead of using sublimated aluminum tri-chloride vapor (AlCl3) as an aluminum source in the vapor phase nitriding reaction, the mixed aluminum chloride vapor consisted of aluminum tri-chloride, bi-chloride and mono-chloride are used in the reaction with ammonia at temperatures of 1000 and 1200K. The mixed chloride vapors are produced by reacting chlorine with molten aluminum at 1000 or 1200K under atmospheric pressure. The reaction of this mixed chloride vapor with ammonia is then experimentally investigated to study the aluminum nitride powder morphology. The aluminum nitride powders synthesized under various ammonia concentrations are characterized for size distribution, mean particle size and particle morphology. 24 refs., 8 figs., 2 tabs.

  11. An improved method for preparing silicon carbide

    International Nuclear Information System (INIS)

    Baney, R.H.

    1980-01-01

    A desired shape is formed from a polysilane and the shape is heated in an inert atmosphere or under vacuum to 1150 to 1600 0 C until the polysilane is converted to silicon carbide. The polysilane contains from 0 to 60 mole percent of (CH 3 ) 2 Si units and from 40 to 100 mole percent of CH 3 Si units. The remaining bonds on silicon are attached to another silicon atom or to a chlorine or bromine atom, such that the polysilane contains from 10 to 43 weight percent of hydrolyzable chlorine or from 21 to 63 weight percent of hydrolyzable bromine. (author)

  12. Oxidation kinetics of CVD silicon carbide and silicon nitride

    Science.gov (United States)

    Fox, Dennis S.

    1992-01-01

    The long-term oxidation behavior of pure, monolithic CVD SiC and Si3N4 is studied, and the isothermal oxidation kinetics of these two materials are obtained for the case of 100 hrs at 1200-1500 C in flowing oxygen. Estimates are made of lifetimes at the various temperatures investigated. Parabolic rate constants for SiC are within an order of magnitude of shorter exposure time values reported in the literature. The resulting silica scales are in the form of cristobalite, with cracks visible after exposure. The oxidation protection afforded by silica for these materials is adequate for long service times under isothermal conditions in 1-atm dry oxygen.

  13. Metal Nitrides for Plasmonic Applications

    DEFF Research Database (Denmark)

    Naik, Gururaj V.; Schroeder, Jeremy; Guler, Urcan

    2012-01-01

    Metal nitrides as alternatives to metals such as gold could offer many advantages when used as plasmonic material. We show that transition metal nitrides can replace metals providing equally good optical performance for many plasmonic applications.......Metal nitrides as alternatives to metals such as gold could offer many advantages when used as plasmonic material. We show that transition metal nitrides can replace metals providing equally good optical performance for many plasmonic applications....

  14. Properties of minor actinide nitrides

    International Nuclear Information System (INIS)

    Takano, Masahide; Itoh, Akinori; Akabori, Mitsuo; Arai, Yasuo; Minato, Kazuo

    2004-01-01

    The present status of the research on properties of minor actinide nitrides for the development of an advanced nuclear fuel cycle based on nitride fuel and pyrochemical reprocessing is described. Some thermal stabilities of Am-based nitrides such as AmN and (Am, Zr)N were mainly investigated. Stabilization effect of ZrN was cleary confirmed for the vaporization and hydrolytic behaviors. New experimental equipments for measuring thermal properties of minor actinide nitrides were also introduced. (author)

  15. Chlorine transportation risk assessment

    International Nuclear Information System (INIS)

    Lautkaski, Risto; Mankamo, Tuomas.

    1977-02-01

    An assessment has been made on the toxication risk of the population due to the bulk rail transportation of liquid chlorine in Finland. Fourteen typical rail accidents were selected and their probability was estimated using the accident file of the Finnish State Railways. The probability of a chlorine leak was assessed for each type of accident separately using four leak size categories. The assessed leakage probability was dominated by station accidents, especially by collisions of a chlorine tanker and a locomotive. Toxication hazard areas were estimated for the leak categories. A simple model was constructed to describe the centring of the densely populated areas along the railway line. A comparison was made between the obtained risk and some other risks including those due to nuclear reactor accidents. (author)

  16. Chlorination leaching of cadmium

    International Nuclear Information System (INIS)

    Lach, E.; Pajak, I.; Bojanowska, A.

    1978-01-01

    The results of the investigations on chlorination leaching of cadmium from dust coming from dry dust collector of sinter belt, that is leaching with water saturated with gaseous chlorine and leaching with solutions of ammonium chloride and sodium chloride were given. The optimum conditions for these processes were established. It was found, that the method of leaching in the presence of gaseous chlorine is more effective, as it allows to report into the solution over 90% cadmium contained in dust. Owing to technical difficulties, environmental protection and safety conditions more advantageous seems to be the use as leaching agent of the ammonium chloride solutions. When applying 20% NH 4 Cl and temperature of 60 0 C, the time of 2 hours and the ratio of solid to liquid of 1:5, 70% cadmium contained in the dust can be reported into the solution. (auth.)

  17. Transferrable monolithic III-nitride photonic circuit for multifunctional optoelectronics

    Science.gov (United States)

    Shi, Zheng; Gao, Xumin; Yuan, Jialei; Zhang, Shuai; Jiang, Yan; Zhang, Fenghua; Jiang, Yuan; Zhu, Hongbo; Wang, Yongjin

    2017-12-01

    A monolithic III-nitride photonic circuit with integrated functionalities was implemented by integrating multiple components with different functions into a single chip. In particular, the III-nitride-on-silicon platform is used as it integrates a transmitter, a waveguide, and a receiver into a suspended III-nitride membrane via a wafer-level procedure. Here, a 0.8-mm-diameter suspended device architecture is directly transferred from silicon to a foreign substrate by mechanically breaking the support beams. The transferred InGaN/GaN multiple-quantum-well diode (MQW-diode) exhibits a turn-on voltage of 2.8 V with a dominant electroluminescence peak at 453 nm. The transmitter and receiver share an identical InGaN/GaN MQW structure, and the integrated photonic circuit inherently works for on-chip power monitoring and in-plane visible light communication. The wire-bonded monolithic photonic circuit on glass experimentally demonstrates in-plane data transmission at 120 Mb/s, paving the way for diverse applications in intelligent displays, in-plane light communication, flexible optical sensors, and wearable III-nitride optoelectronics.

  18. Effect of boron nitride coating on fiber-matrix interactions

    International Nuclear Information System (INIS)

    Singh, R.N.; Brun, M.K.

    1987-01-01

    Coatings can modify fiber-matrix reactions and consequently interfacial bond strengths. Commercially available mullite, silicon carbide, and carbon fibers were coated with boron nitride via low pressure chemical vapor deposition and incorporated into a mullite matrix by hot-pressing. The influence of fiber-matrix interactions for uncoated fibers on fracture morphologies was studied. These observations are related to the measured values of interfacial shear strengths

  19. Enhanced light emission in photonic crystal nanocavities with Erbium-doped silicon nanocrystals

    International Nuclear Information System (INIS)

    Makarova, Maria; Sih, Vanessa; Vuckovic, Jelena; Warga, Joe; Li Rui; Dal Negro, Luca

    2008-01-01

    Photonic crystal nanocavities are fabricated in silicon membranes covered by thermally annealed silicon-rich nitride films with Erbium-doped silicon nanocrystals. Silicon nitride films were deposited by sputtering on top of silicon on insulator wafers. The nanocavities were carefully designed in order to enhance emission from the nanocrystal sensitized Erbium at the 1540 nm wavelength. Experimentally measured quality factors of ∼6000 were found to be consistent theoretical predictions. The Purcell factor of 1.4 was estimated from the observed 20-fold enhancement of Erbium luminescence

  20. Surface Texturing-Plasma Nitriding Duplex Treatment for Improving Tribological Performance of AISI 316 Stainless Steel

    Directory of Open Access Journals (Sweden)

    Naiming Lin

    2016-10-01

    Full Text Available Surface texturing-plasma nitriding duplex treatment was conducted on AISI 316 stainless steel to improve its tribological performance. Tribological behaviors of ground 316 substrates, plasma-nitrided 316 (PN-316, surface-textured 316 (ST-316, and duplex-treated 316 (DT-316 in air and under grease lubrication were investigated using a pin-on-disc rotary tribometer against counterparts of high carbon chromium bearing steel GCr15 and silicon nitride Si3N4 balls. The variations in friction coefficient, mass loss, and worn trace morphology of the tested samples were systemically investigated and analyzed. The results showed that a textured surface was formed on 316 after electrochemical processing in a 15 wt % NaCl solution. Grooves and dimples were found on the textured surface. As plasma nitriding was conducted on a 316 substrate and ST-316, continuous and uniform nitriding layers were successfully fabricated on the surfaces of the 316 substrate and ST-316. Both of the obtained nitriding layers presented thickness values of more than 30 μm. The nitriding layers were composed of iron nitrides and chromium nitride. The 316 substrate and ST-316 received improved surface hardness after plasma nitriding. When the tribological tests were carried out under dry sliding and grease lubrication conditions, the tested samples showed different tribological behaviors. As expected, the DT-316 samples revealed the most promising tribological properties, reflected by the lowest mass loss and worn morphologies. The DT-316 received the slightest damage, and its excellent tribological performance was attributed to the following aspects: firstly, the nitriding layer had high surface hardness; secondly, the surface texture was able to capture wear debris, store up grease, and then provide continuous lubrication.

  1. Where does Chlorine-36 go?

    International Nuclear Information System (INIS)

    Anon.

    2000-01-01

    Chlorine-36 and Iodine-129 are the unique long-life radionuclides in the halogen family and halogens are known to be very mobile in the environment. Chlorine-36 is present in slight quantities in radioactive wastes containing carbon or issued from spent fuel reprocessing. The migration of Chlorine-36 in the environment has been very little studied, so a collaboration between the French institute of protection and nuclear safety (IPSN) and the Ukrainian institute for agricultural radioecology (UIAR) has been launched. IPSN will study the migration of Chlorine-36 in soils and UIAR will be in charge of studying the transfer of Chlorine-36 from soil to plants. (A.C.)

  2. Chemical-vapor-infiltrated silicon nitride, boron nitride, and silicon carbide matrix composites

    International Nuclear Information System (INIS)

    Ventri, R.D.; Galasso, F.S.

    1990-01-01

    This paper reports composites of carbon/chemical-vapor-deposited (CVD) Si 3 N 4 , carbon/CVD BN, mullite/CVD SiC, and SiC yarn/CVD SiC prepared to determine if there were inherent toughness in these systems. The matrices were deposited at high enough temperatures to ensure that they were crystalline, which should make them more stable at high temperatures. The fiber-matrix bonding in the C/Si 3 N 4 composite appeared to be too strong; the layers of BN in the matrix of the C/BN were too weakly bonded; and the mullite/SiC composite was not as tough as the SiC/SiC composites. Only the SiC yarn/CVD SiC composite exhibited both strength and toughness

  3. Nitriding of high speed steel

    International Nuclear Information System (INIS)

    Doyle, E.D.; Pagon, A.M.; Hubbard, P.; Dowey, S.J.; Pilkington, A.; McCulloch, D.G.; Latham, K.; DuPlessis, J.

    2010-01-01

    Current practice when nitriding HSS cutting tools is to avoid embrittlement of the cutting edge by limiting the depth of the diffusion zone. This is accomplished by reducing the nitriding time and temperature and eliminating any compound layer formation. However, in many applications there is an argument for generating a compound layer with beneficial tribological properties. In this investigation results are presented of a metallographic, XRD and XPS analysis of nitrided surface layers generated using active screen plasma nitriding and reactive vapour deposition using cathodic arc. These results are discussed in the context of built up edge formation observed while machining inside a scanning electron microscope. (author)

  4. Defects in dilute nitrides

    International Nuclear Information System (INIS)

    Chen, W.M.; Buyanova, I.A.; Tu, C.W.; Yonezu, H.

    2005-01-01

    We provide a brief review our recent results from optically detected magnetic resonance studies of grown-in non-radiative defects in dilute nitrides, i.e. Ga(In)NAs and Ga(Al,In)NP. Defect complexes involving intrinsic defects such as As Ga antisites and Ga i self interstitials were positively identified.Effects of growth conditions, chemical compositions and post-growth treatments on formation of the defects are closely examined. These grown-in defects are shown to play an important role in non-radiative carrier recombination and thus in degrading optical quality of the alloys, harmful to performance of potential optoelectronic and photonic devices based on these dilute nitrides. (author)

  5. Chlorination of zirconyte concentrate

    International Nuclear Information System (INIS)

    Costa, N.G.

    1988-01-01

    Chlorination experiments with zirconyte concentrate were carried out in order to study the effects of temperature, percentage of reducing agent and porosity on the gasification of ZrO 2 for 10 and 20 minutes of reaction. Factorial analysis was applied and the results indicated that temperature and percentage of reducing agent were the two only variables effecting the ZrO 2 gasification. (author) [pt

  6. Photo-Electrical Characterization of Silicon Micropillar Arrays with Radial p/n Junctions Containing Passivation and Anti-Reflection Coatings

    NARCIS (Netherlands)

    Vijselaar, Wouter; Elbersen, R.; Tiggelaar, Roald M.; Gardeniers, Han; Huskens, Jurriaan

    2017-01-01

    In order to assess the contributions of anti-reflective and passivation effects in microstructured silicon-based solar light harvesting devices, thin layers of aluminum oxide (Al2O3), silicon dioxide (SiO2), silicon-rich silicon nitride (SiNx), and indium tin oxide (ITO), with a thickness ranging

  7. Fully CMOS-compatible titanium nitride nanoantennas

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, Justin A., E-mail: jabriggs@stanford.edu [Department of Applied Physics, Stanford University, 348 Via Pueblo Mall, Stanford, California 94305 (United States); Department of Materials Science and Engineering, Stanford University, 496 Lomita Mall, Stanford, California 94305 (United States); Naik, Gururaj V.; Baum, Brian K.; Dionne, Jennifer A. [Department of Materials Science and Engineering, Stanford University, 496 Lomita Mall, Stanford, California 94305 (United States); Petach, Trevor A.; Goldhaber-Gordon, David [Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, California 94305 (United States)

    2016-02-01

    CMOS-compatible fabrication of plasmonic materials and devices will accelerate the development of integrated nanophotonics for information processing applications. Using low-temperature plasma-enhanced atomic layer deposition (PEALD), we develop a recipe for fully CMOS-compatible titanium nitride (TiN) that is plasmonic in the visible and near infrared. Films are grown on silicon, silicon dioxide, and epitaxially on magnesium oxide substrates. By optimizing the plasma exposure per growth cycle during PEALD, carbon and oxygen contamination are reduced, lowering undesirable loss. We use electron beam lithography to pattern TiN nanopillars with varying diameters on silicon in large-area arrays. In the first reported single-particle measurements on plasmonic TiN, we demonstrate size-tunable darkfield scattering spectroscopy in the visible and near infrared regimes. The optical properties of this CMOS-compatible material, combined with its high melting temperature and mechanical durability, comprise a step towards fully CMOS-integrated nanophotonic information processing.

  8. Organization of silicon nanocrystals by localized electrochemical etching

    International Nuclear Information System (INIS)

    Ayari-Kanoun, Asma; Drouin, Dominique; Beauvais, Jacques; Lysenko, Vladimir; Nychyporuk, Tetyana; Souifi, Abdelkader

    2009-01-01

    An approach to form a monolayer of organized silicon nanocrystals on a monocrystalline Si wafer is reported. Ordered arrays of nanoholes in a silicon nitride layer were obtained by combining electron beam lithography and plasma etching. Then, a short electrochemical etching current pulse led to formation of a single Si nanocrystal per each nanohole. As a result, high quality silicon nanocrystal arrays were formed with well controlled and reproducible morphologies. In future, this approach can be used to fabricate single electron devices.

  9. Plasmonic Titanium Nitride Nanostructures via Nitridation of Nanopatterned Titanium Dioxide

    DEFF Research Database (Denmark)

    Guler, Urcan; Zemlyanov, Dmitry; Kim, Jongbum

    2017-01-01

    Plasmonic titanium nitride nanostructures are obtained via nitridation of titanium dioxide. Nanoparticles acquired a cubic shape with sharper edges following the rock-salt crystalline structure of TiN. Lattice constant of the resulting TiN nanoparticles matched well with the tabulated data. Energy...

  10. Boron nitride: A new photonic material

    International Nuclear Information System (INIS)

    Chubarov, M.; Pedersen, H.; Högberg, H.; Filippov, S.; Engelbrecht, J.A.A.; O'Connel, J.; Henry, A.

    2014-01-01

    Rhombohedral boron nitride (r-BN) layers were grown on sapphire substrate in a hot-wall chemical vapor deposition reactor. Characterization of these layers is reported in details. X-ray diffraction (XRD) is used as a routine characterization tool to investigate the crystalline quality of the films and the identification of the phases is revealed using detailed pole figure measurements. Transmission electron microscopy reveals stacking of more than 40 atomic layers. Results from Fourier Transform InfraRed (FTIR) spectroscopy measurements are compared with XRD data showing that FTIR is not phase sensitive when various phases of sp 2 -BN are investigated. XRD measurements show a significant improvement of the crystalline quality when adding silicon to the gas mixture during the growth; this is further confirmed by cathodoluminescence which shows a decrease of the defects related luminescence intensity.

  11. Boron nitride: A new photonic material

    Energy Technology Data Exchange (ETDEWEB)

    Chubarov, M., E-mail: mihcu@ifm.liu.se [Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping (Sweden); Pedersen, H., E-mail: henke@ifm.liu.se [Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping (Sweden); Högberg, H., E-mail: hanho@ifm.liu.se [Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping (Sweden); Filippov, S., E-mail: stafi@ifm.liu.se [Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping (Sweden); Engelbrecht, J.A.A., E-mail: Japie.Engelbrecht@nmmu.ac.za [Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); O' Connel, J., E-mail: jacques.oconnell@gmail.com [Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Henry, A., E-mail: anne.henry@liu.se [Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping (Sweden)

    2014-04-15

    Rhombohedral boron nitride (r-BN) layers were grown on sapphire substrate in a hot-wall chemical vapor deposition reactor. Characterization of these layers is reported in details. X-ray diffraction (XRD) is used as a routine characterization tool to investigate the crystalline quality of the films and the identification of the phases is revealed using detailed pole figure measurements. Transmission electron microscopy reveals stacking of more than 40 atomic layers. Results from Fourier Transform InfraRed (FTIR) spectroscopy measurements are compared with XRD data showing that FTIR is not phase sensitive when various phases of sp{sup 2}-BN are investigated. XRD measurements show a significant improvement of the crystalline quality when adding silicon to the gas mixture during the growth; this is further confirmed by cathodoluminescence which shows a decrease of the defects related luminescence intensity.

  12. Optical characterization of gallium nitride

    NARCIS (Netherlands)

    Kirilyuk, Victoria

    2002-01-01

    Group III-nitrides have been considered a promising system for semiconductor devices since a few decades, first for blue- and UV-light emitting diodes, later also for high-frequency/high-power applications. Due to the lack of native substrates, heteroepitaxially grown III-nitride layers are usually

  13. Use of cermet thin film resistors with nitride passivated metal insulator field effect transistor

    Science.gov (United States)

    Brown, G. A.; Harrap, V.

    1971-01-01

    Film deposition of cermet resistors on same chip with metal nitride oxide silicon field effect transistors permits protection of contamination sensitive active devices from contaminants produced in cermet deposition and definition processes. Additional advantages include lower cost, greater reliability, and space savings.

  14. Electrical characterization of high-pressure reactive sputtered ScOx films on silicon

    International Nuclear Information System (INIS)

    Castan, H.; Duenas, S.; Gomez, A.; Garcia, H.; Bailon, L.; Feijoo, P.C.; Toledano-Luque, M.; Prado, A. del; San Andres, E.; Lucia, M.L.

    2011-01-01

    Al/ScO x /SiN x /n-Si and Al/ScO x /SiO x /n-Si metal-insulator-semiconductor capacitors have been electrically characterized. Scandium oxide was grown by high-pressure sputtering on different substrates to study the dielectric/insulator interface quality. The substrates were silicon nitride and native silicon oxide. The use of a silicon nitride interfacial layer between the silicon substrate and the scandium oxide layer improves interface quality, as interfacial state density and defect density inside the insulator are decreased.

  15. The behavior of SiC and Si3N4 ceramics in mixed oxidation/chlorination environments

    Science.gov (United States)

    Marra, John E.; Kreidler, Eric R.; Jacobson, Nathan S.; Fox, Dennis S.

    1989-01-01

    The behavior of silicon-based ceramics in mixed oxidation/chlorination environments was studied. High pressure mass spectrometry was used to quantitatively identify the reaction products. The quantitative identification of the corrosion products was coupled with thermogravimetric analysis and thermodynamic equilibrium calculations run under similar conditions in order to deduce the mechanism of corrosion. Variations in the behavior of the different silicon-based materials are discussed. Direct evidence of the existence of silicon oxychloride compounds is presented.

  16. Hot pressing of uranium nitride and mixed uranium plutonium nitride

    International Nuclear Information System (INIS)

    Chang, J.Y.

    1975-01-01

    The hot pressing characteristics of uranium nitride and mixed uranium plutonium nitride were studied. The utilization of computer programs together with the experimental technique developed in the present study may serve as a useful purpose of prediction and fabrication of advanced reactor fuel and other high temperature ceramic materials for the future. The densification of nitrides follow closely with a plastic flow theory expressed as: d rho/ dt = A/T(t) (1-rho) [1/1-(1-rho)/sup 2/3/ + B1n (1-rho)] The coefficients, A and B, were obtained from experiment and computer curve fitting. (8 figures) (U.S.)

  17. Silicone metalization

    Energy Technology Data Exchange (ETDEWEB)

    Maghribi, Mariam N. (Livermore, CA); Krulevitch, Peter (Pleasanton, CA); Hamilton, Julie (Tracy, CA)

    2008-12-09

    A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.

  18. Electrospun Gallium Nitride Nanofibers

    International Nuclear Information System (INIS)

    Melendez, Anamaris; Morales, Kristle; Ramos, Idalia; Campo, Eva; Santiago, Jorge J.

    2009-01-01

    The high thermal conductivity and wide bandgap of gallium nitride (GaN) are desirable characteristics in optoelectronics and sensing applications. In comparison to thin films and powders, in the nanofiber morphology the sensitivity of GaN is expected to increase as the exposed area (proportional to the length) increases. In this work we present electrospinning as a novel technique in the fabrication of GaN nanofibers. Electrospinning, invented in the 1930s, is a simple, inexpensive, and rapid technique to produce microscopically long ultrafine fibers. GaN nanofibers are produced using gallium nitrate and dimethyl-acetamide as precursors. After electrospinning, thermal decomposition under an inert atmosphere is used to pyrolyze the polymer. To complete the preparation, the nanofibers are sintered in a tube furnace under a NH 3 flow. Both scanning electron microscopy and profilometry show that the process produces continuous and uniform fibers with diameters ranging from 20 to a few hundred nanometers, and lengths of up to a few centimeters. X-ray diffraction (XRD) analysis shows the development of GaN nanofibers with hexagonal wurtzite structure. Future work includes additional characterization using transmission electron microscopy and XRD to understand the role of precursors and nitridation in nanofiber synthesis, and the use of single nanofibers for the construction of optical and gas sensing devices.

  19. Gallium nitride-based micro-opto-electro-mechanical systems

    Science.gov (United States)

    Stonas, Andreas Robert

    Gallium Nitride and its associated alloys InGaN and AlGaN have many material properties that are highly desirable for micro-electro-mechanical systems (MEMS), and more specifically micro-opto-electro-mechanical systems (MOEMS). The group III-nitrides are tough, stiff, optically transparent, direct bandgap, chemically inert, highly piezoelectric, and capable of functioning at high temperatures. There is currently no other semiconductor system that possesses all of these properties. Taken together, these attributes make the nitrides prime candidates not only for creating new versions of existing device structures, but also for creating entirely unique devices which combine these properties in novel ways. Unfortunately, their chemical resiliency also makes the group III-nitrides extraordinarily difficult to shape into devices. In particular, until this research, no undercut etch technology existed that could controllably separate a selected part of a MEMS device from its sapphire or silicon carbide substrate. This has effectively prevented GaN-based MEMS from being developed. This dissertation describes how this fabrication obstacle was overcome by a novel etching geometry (bandgap-selective backside-illuminated photoelectochemical (BS-BIPEC) etching) and its resulting morphologies. Several gallium-nitride based MEMS devices were created, actuated, and modelled, including cantilevers and membranes. We describe in particular our pursuit of one of the many novel device elements that is possible only in this material system: a transducer that uses an externally applied strain to dynamically change the optical transition energy of a quantum well. While the device objective of a dynamically tunable quantum well was not achieved, we have demonstrated sufficient progress to believe that such a device will be possible soon. We have observed a shift (5.5meV) of quantum well transition energies in released structures, and we have created structures that can apply large biaxial

  20. Studies with solid chlorine chemical for chlorination of sea water systems

    International Nuclear Information System (INIS)

    Sankar, N.; Kumaraswamy, P.; Santhanam, V.S.; Jeena, P.; Hari Krishna, K.; Rajendran, D.

    2015-01-01

    Chlorination is one of the conventional methods to control biofouling of condenser cooling water systems using either river water, reservoir water or sea water. However, there are many safety concerns associated with handling, storage and application of gaseous chlorine. Studies were carried out with suitable alternative chlorine chemical compounds which do not involve majority of these concerns but meet the functional requirement of gas chlorine. Trichloroisocyanuric Acid (TCCA) is one of the suitable alternatives to Gas chlorine. TCCA is a chlorine stabilized compound, stabilized with Cyanuric acid, thus similar to Gas Chlorine in its functions except that it is available in solid form. Release of chlorine is a gradual process in TCCA unlike Gaseous chlorine. Field studies with TCCA indicated gradual and near uniform release rate of chlorine, for longer duration with the requisite free residual chlorine levels (FRC). Thus, use of TCCA could be considered as a suitable alternative for gas chlorine for regular chlorination requirements. (author)

  1. UV radiation hardness of silicon inversion layer solar cells

    International Nuclear Information System (INIS)

    Hezel, R.

    1990-01-01

    For full utilization of the high spectral response of inversion layer solar cells in the very-short-wavelength range of the solar spectrum sufficient ultraviolet-radiation hardness is required. In addition to the charge-induced passivation achieved by cesium incorporation into the silicon nitride AR coating, in this paper the following means for further drastic reduction of UV light-induced effects in inversion layer solar cells without encapsulation are introduced and interpretations are given: increasing the nitride deposition temperature, silicon surface oxidation at low temperatures, and texture etching and using higher substrate resistivities. High UV radiation tolerance and improvement of the cell efficiency could be obtained simultaneously

  2. Method for producing polycrystalline boron nitride

    International Nuclear Information System (INIS)

    Alexeevskii, V.P.; Bochko, A.V.; Dzhamarov, S.S.; Karpinos, D.M.; Karyuk, G.G.; Kolomiets, I.P.; Kurdyumov, A.V.; Pivovarov, M.S.; Frantsevich, I.N.; Yarosh, V.V.

    1975-01-01

    A mixture containing less than 50 percent of graphite-like boron nitride treated by a shock wave and highly defective wurtzite-like boron nitride obtained by a shock-wave method is compressed and heated at pressure and temperature values corresponding to the region of the phase diagram for boron nitride defined by the graphite-like compact modifications of boron nitride equilibrium line and the cubic wurtzite-like boron nitride equilibrium line. The resulting crystals of boron nitride exhibit a structure of wurtzite-like boron nitride or of both wurtzite-like and cubic boron nitride. The resulting material exhibits higher plasticity as compared with polycrystalline cubic boron nitride. Tools made of this compact polycrystalline material have a longer service life under impact loads in machining hardened steel and chilled iron. (U.S.)

  3. Zirconium nitride hard coatings

    International Nuclear Information System (INIS)

    Roman, Daiane; Amorim, Cintia Lugnani Gomes de; Soares, Gabriel Vieira; Figueroa, Carlos Alejandro; Baumvol, Israel Jacob Rabin; Basso, Rodrigo Leonardo de Oliveira

    2010-01-01

    Zirconium nitride (ZrN) nanometric films were deposited onto different substrates, in order to study the surface crystalline microstructure and also to investigate the electrochemical behavior to obtain a better composition that minimizes corrosion reactions. The coatings were produced by physical vapor deposition (PVD). The influence of the nitrogen partial pressure, deposition time and temperature over the surface properties was studied. Rutherford backscattering spectrometry (RBS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and corrosion experiments were performed to characterize the ZrN hard coatings. The ZrN films properties and microstructure changes according to the deposition parameters. The corrosion resistance increases with temperature used in the films deposition. Corrosion tests show that ZrN coating deposited by PVD onto titanium substrate can improve the corrosion resistance. (author)

  4. Pyrochemical reprocessing of nitride fuel

    International Nuclear Information System (INIS)

    Nakazono, Yoshihisa; Iwai, Takashi; Arai, Yasuo

    2004-01-01

    Electrochemical behavior of actinide nitrides in LiCl-KCl eutectic melt was investigated in order to apply pyrochemical process to nitride fuel cycle. The electrode reaction of UN and (U, Nd)N was examined by cyclic voltammetry. The observed rest potential of (U, Nd)N depended on the equilibrium of U 3+ /UN and was not affected by the addition of NdN of 8 wt.%. (author)

  5. Chloride pyrometallurgy of uranium ore. 1. Chlorination of phosphate ore using solid or gas chlorinating agent and carbon

    International Nuclear Information System (INIS)

    Taki, Tomihiro; Komoto, Shigetoshi; Otomura, Keiichiro; Takenaka, Toshihide; Sato, Nobuaki; Fujino, Takeo.

    1995-01-01

    A thermodynamical and pyrometallurgical study to recover uranium from the phosphate ores was undertaken using the chloride volatilization method. Iron was chlorinated with solid chlorinating agents such as NaCl and CaCl 2 in combination with activated carbon, which will be used for removing this element from the ore, but uranium was not. On the other hand, the chlorination using Cl 2 gas and activated carbon gave a good result at 1,223 K. Not only uranium but also iron, phosphorus, aluminum and silicon were found to form volatile chlorides which vaporized out of the ore, while calcium remained in the ore as non-volatile CaCl 2 . The chlorination condition was studied as functions of temperature, reaction time and carbon content. The volatilization ratio of uranium around 95% was obtained by heating the mixture of the ore and activated carbon (35 wt%) in a mixed gas flow of Cl 2 (200 ml/min) and N 2 (200 ml/min) at 1,223 K for 120 min. (author)

  6. Photodynamic tissue adhesion with chlorin(e6) protein conjugates.

    Science.gov (United States)

    Khadem, J; Veloso, A A; Tolentino, F; Hasan, T; Hamblin, M R

    1999-12-01

    To test the hypothesis that a photodynamic laser-activated tissue solder would perform better in sealing scleral incisions when the photosensitizer was covalently linked to the protein than when it was noncovalently mixed. Conjugates and mixtures were prepared between the photosensitizer chlorin(e6) and various proteins (albumin, fibrinogen, and gelatin) in different ratios and used to weld penetrating scleral incisions made in human cadaveric eyes. A blue-green (488-514 nm) argon laser activated the adhesive, and the strength of the closure was measured by increasing the intraocular pressure until the wound showed leakage. Both covalent conjugates and noncovalent mixtures showed a light dose-dependent increase in leaking pressure. A preparation of albumin chlorin(e6) conjugate with additional albumin added (2.5 protein to chlorin(e6) molar ratio) showed significantly higher weld strength than other protein conjugates and mixtures. This is the first report of dye-protein conjugates as tissue solders. These conjugates may have applications in ophthalmology.

  7. Nitride stabilized core/shell nanoparticles

    Science.gov (United States)

    Kuttiyiel, Kurian Abraham; Sasaki, Kotaro; Adzic, Radoslav R.

    2018-01-30

    Nitride stabilized metal nanoparticles and methods for their manufacture are disclosed. In one embodiment the metal nanoparticles have a continuous and nonporous noble metal shell with a nitride-stabilized non-noble metal core. The nitride-stabilized core provides a stabilizing effect under high oxidizing conditions suppressing the noble metal dissolution during potential cycling. The nitride stabilized nanoparticles may be fabricated by a process in which a core is coated with a shell layer that encapsulates the entire core. Introduction of nitrogen into the core by annealing produces metal nitride(s) that are less susceptible to dissolution during potential cycling under high oxidizing conditions.

  8. Feasibility study of self-lubrication by chlorine implantation

    International Nuclear Information System (INIS)

    Akhajdenung, T.; Aizawa, T.; Yoshitake, M.; Mitsuo, A.

    2003-01-01

    Implantation of chlorine into titanium nitride (TiN) coating on the high-speed steel substrate has succeeded in significant reduction of wear rate and friction coefficient for original TiN under dry wear condition. Through precise investigation on the surface reaction in the wear track, in situ formation of oxygen-deficient titanium oxides was found to play a role as a lubricious oxide. In the present paper, this self-lubrication mechanism is further investigated for various wearing conditions. For wide range of sliding speed and normal load in the wear map, the wear volume of a counter material is actually reduced with comparison to the un-implanted TiN. Effect of the ion implantation dose on this self-lubrication mechanism is also studied for practical use. Some comments are made on further application of this self-lubrication to manufacturing

  9. Effects of varying oxygen partial pressure on molten silicon-ceramic substrate interactions

    Science.gov (United States)

    Ownby, D. P.; Barsoum, M. W.

    1980-01-01

    The silicon sessile drop contact angle was measured on hot pressed silicon nitride, silicon nitride coated on hot pressed silicon nitride, silicon carbon coated on graphite, and on Sialon to determine the degree to which silicon wets these substances. The post-sessile drop experiment samples were sectioned and photomicrographs were taken of the silicon-substrate interface to observe the degree of surface dissolution and degradation. Of these materials, silicon did not form a true sessile drop on the SiC on graphite due to infiltration of the silicon through the SiC coating, nor on the Sialon due to the formation of a more-or-less rigid coating on the liquid silicon. The most wetting was obtained on the coated Si3N4 with a value of 42 deg. The oxygen concentrations in a silicon ribbon furnace and in a sessile drop furnace were measured using the protable thoria-yttria solid solution electrolyte oxygen sensor. Oxygen partial pressures of 10 to the minus 7 power atm and 10 to the minus 8 power atm were obtained at the two facilities. These measurements are believed to represent nonequilibrium conditions.

  10. Development and set-up of a test system for non-destructive acoustic and ultrasonic testing of silicon nitride ceramics valves; Entwicklung und Aufbau eines Pruefsystems zur zerstoerungsfreien Klang- und Ultraschallpruefung von Ventilen aus Siliciumnitrid-Keramik

    Energy Technology Data Exchange (ETDEWEB)

    Lindner, H.A.; Caspers, B.; Hennicke, J.; Feuer, H.; Petzenhauser, I. [Cremer Forschungsinstitut GmbH und Co. KG, Roedental (Germany)

    1999-07-01

    Valves made of silicon nitrice ceramics have advantages over metal valves owing to their low density, high wear resistance, low thermal conductivity and high termperature resistance. Reciprocating piston engines with ceramic valves have a lower fuel consumption, lower noise, and lower exhaust emissions. On the other hand, ceramic materials have the disadvantage of being brittele, i.e. mechanical stress concentrations at crack tips cannot be removed by plastic deformation. In order to ensure safe application in piston engines, all ceramic valves must therefore be tested by nondestructive methods in order to detect and replace defective valves. [German] Ventile aus Siliciumnitrid-Keramik haben infolge ihrer geringen Dichte, hohen Verschleissfestigkeit, niedrigen Waermeleitfaehigkeit und hohen Temperaturfestigkeit gegenueber Ventilen aus metallischen Werkstoffen ganz entscheidende Vorteile. So haben Hubkolbenmotoren mit Keramikventilen einen deutlich geringeren Treibstoffbedarf und zeigen bei einem erheblich reduzierten Geraeuschpegel eine schadstoffaermere Abgasentwicklung. Diesen Vorteilen steht die allen keramischen Werkstoffen gemeinsame Eigenschaft der Sproedigkeit gegenueber. So koennen mechanische Spannungskonzentrationen an Rissspitzen nicht durch plastische Verformung abgebaut werden. Fuer den sicheren Einsatz im Hubkolbenmotor muessen daher die Keramikventile einer zerstoerungsfreien Bewertung unterzogen werden, um fehlerhafte Ventile zu erkennen und auszuscheiden. (orig.)

  11. Grundfoss: Chlorination of Swimming Pools

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Hogan, John; Andreassen, Viggo

    1998-01-01

    Grundfos asked for a model, describing the problem of mixing chemicals, being dosed into water systems, to be developed. The application of the model should be dedicated to dosing aqueous solution of chlorine into swimming pools.......Grundfos asked for a model, describing the problem of mixing chemicals, being dosed into water systems, to be developed. The application of the model should be dedicated to dosing aqueous solution of chlorine into swimming pools....

  12. Aluminum nitride insulating films for MOSFET devices

    Science.gov (United States)

    Lewicki, G. W.; Maserjian, J.

    1972-01-01

    Application of aluminum nitrides as electrical insulator for electric capacitors is discussed. Electrical properties of aluminum nitrides are analyzed and specific use with field effect transistors is defined. Operational limits of field effect transistors are developed.

  13. Study the gas sensing properties of boron nitride nanosheets

    International Nuclear Information System (INIS)

    Sajjad, Muhammad; Feng, Peter

    2014-01-01

    Graphical abstract: - Highlights: • We synthesized boron nitride nanosheets (BNNSs) on silicon substrate. • We analyzed gas sensing properties of BNNSs-based gas-sensor device. • CH 4 gas is used to measure gas-sensing properties of the device. • Quick response and recovery time of the device is recorded. • BNNSs showed excellent sensitivity to the working gas. - Abstract: In the present communication, we report on the synthesis of boron nitride nanosheets (BNNSs) and study of their gas sensing properties. BNNSs are synthesized by irradiating pyrolytic hexagonal boron nitride (h-BN) target using CO 2 laser pulses. High resolution transmission electron microscopic measurements (HRTEM) revealed 2-dientional honeycomb crystal lattice structure of BNNSs. HRTEM, electron diffraction, XRD and Raman scattering measurements clearly identified h-BN. Gas sensing properties of synthesized BNNSs were analyzed with prototype gas sensor using methane as working gas. A systematic response curve of the sensor is recorded in each cycle of gas “in” and “out”; suggesting excellent sensitivity and high performance of BNNSs-based gas-sensor

  14. Fabrication of vanadium nitride by carbothermal nitridation reaction

    International Nuclear Information System (INIS)

    Wang Xitang; Wang Zhuofu; Zhang Baoguo; Deng Chengji

    2005-01-01

    Vanadium nitride is produced from V 2 O 5 by carbon-thermal reduction and nitridation. When the sintered temperature is above 1273 K, VN can be formed, and the nitrogen content of the products increased with the firing temperature raised, and then is the largest when the sintered temperature is 1573 K. The C/V 2 O 5 mass ratio of the green samples is the other key factor affecting on the nitrogen contents of the products. The nitrogen content of the products reaches the most when the C/V 2 O 5 mass ratio is 0.33, which is the theoretical ratio of the carbothermal nitridation of V 2 O 5 . (orig.)

  15. Characterisation of Chlorine Behavior in French Graphite

    International Nuclear Information System (INIS)

    Blondel, A.; Moncoffre, N.; Toulhoat, N.; Bererd, N.; Petit, L.; Laurent, G.; Lamouroux, C.

    2016-01-01

    Chlorine 36 is one of the main radionuclides of concern for French graphite waste disposal. In order to help the understanding of its leaching behaviour under disposal conditions, the respective impact of temperature, irradiation and gas radiolysis on chlorine release in reactor has been studied. Chlorine 36 has been simulated through chlorine 37 ion implantation in virgin nuclear graphite samples. Results show that part of chlorine is highly mobile in graphite in the range of French reactors operating temperatures in relation with graphite structural recovering. Ballistic damage generated by irradiation also promotes chlorine release whereas no clear impact of the coolant gas radiolysis was observed in the absence of graphite radiolytic corrosion. (author)

  16. Enhanced non-radiative energy transfer in hybrid III-nitride structures

    International Nuclear Information System (INIS)

    Smith, R. M.; Athanasiou, M.; Bai, J.; Liu, B.; Wang, T.

    2015-01-01

    The effect of surface states has been investigated in hybrid organic/inorganic white light emitting structures that employ high efficiency, nearfield non-radiative energy transfer (NRET) coupling. The structures utilize blue emitting InGaN/GaN multiple quantum well (MQW) nanorod arrays to minimize the separation with a yellow emitting F8BT coating. Surface states due to the exposed III-nitride surfaces of the nanostructures are found to reduce the NRET coupling rate. The surface states are passivated by deposition of a silicon nitride layer on the III-nitride nanorod surface leading to reduced surface recombination. A low thickness surface passivation is shown to increase the NRET coupling rate by 4 times compared to an un-passivated hybrid structure. A model is proposed to explain the increased NRET rate for the passivated hybrid structures based on the reduction in surface electron depletion of the passivated InGaN/GaN MQW nanorods surfaces

  17. Discrete Charge Storage Nonvolatile Memory Based on Si Nanocrystals with Nitridation Treatment

    International Nuclear Information System (INIS)

    Xian-Gao, Zhang; Kun-Ji, Chen; Zhong-Hui, Fang; Xin-Ye, Qian; Guang-Yuan, Liu; Xiao-Fan, Jiang; Zhong-Yuan, Ma; Jun, Xu; Xin-Fan, Huang; Jian-Xin, Ji; Fei, He; Kuang-Bao, Song; Jun, Zhang; Hui, Wan; Rong-Hua, Wang

    2010-01-01

    A nonvolatile memory device with nitrided Si nanocrystals embedded in a Boating gate was fabricated. The uniform Si nanocrystals with high density (3 × 10 11 cm −2 ) were deposited on ultra-thin tunnel oxide layer (∼ 3 nm) and followed by a nitridation treatment in ammonia to form a thin silicon nitride layer on the surface of nanocrystals. A memory window of 2.4 V was obtained and it would be larger than 1.3 V after ten years from the extrapolated retention data. The results can be explained by the nitrogen passivation of the surface traps of Si nanocrystals, which slows the charge loss rate. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  18. Reactive radio frequency sputtering deposition and characterization of zinc nitride and oxynitride thin films

    International Nuclear Information System (INIS)

    Jiang, Nanke; Georgiev, Daniel G.; Wen, Ting; Jayatissa, Ahalapitiya H.

    2012-01-01

    Zinc nitride films were deposited on glass or silicon substrates by reactive magnetron radio frequency sputtering of zinc in either N 2 –Ar or N 2 –Ar–O 2 ambient. The effects of varying the nitrogen contents and the substrate temperature were investigated. X-ray diffraction data showed that the as-deposited films contain the zinc nitride cubic crystalline phase with a preferred orientation, and Raman scattering measurements revealed Zn-N related modes. According to energy-dispersive X-ray spectroscopy analysis, the as-deposited films were nitrogen-rich and contained only a small fraction of oxygen. Hall-effect measurements showed that p-type zinc nitride with carrier concentration of ∼ 10 19 cm −3 , mobility of ∼ 10 1 cm 2 /Vs, resistivity of ∼ 10 −2 Ω ∗ cm, was obtained. The photon energy dependence of optical transmittance suggested that the material has an indirect bandgap.

  19. Process for producing chlorinated polyethylene

    International Nuclear Information System (INIS)

    Nose, Shinji; Takayama, Shin-ichi; Kodama, Takashi.

    1970-01-01

    A process for chlorinated polyethylene by the chlorination of an aqueous suspension of polyethylene without the use catalysts is given, using 5-55% by gel content of cross-linked polyethylene powders. The products have favorable material workability, transparency, impact strength and tensile properties. In the case of peroxide cross-linking, a mixture of peroxides with polyethylene must be ground after heat treatment. The polyethylene may preferably have a gel content of 5-55%. The chlorination temperature may be 40 0 C or more, preferably 60 0 to 160 0 C. In one example, high pressure polymerized fine polyethylene powders of 15μ having a density of 0.935 g/cc, a softening point of 114 0 C, an average molecular weight of 35,000 were irradiated in air with 40 Mrad electron beams from a 2 MV Cockcroft-Walton type accelerator at room temperature. The thus irradiated polyethylene had a gel content of 55% and a softening point of 119 0 C. It was chlorinated upto a chlorine content of 33% at 100 0 C. Products were white crystals having a melting point of 122 0 C and a melting heat value of 32 mcal/mg. A sheet formed from this product showed a tensile strength of 280 kg/cm 2 , an elongation of 370% and a hardness of 90. (Iwakiri, K.)

  20. Simulation of the Nitriding Process

    Science.gov (United States)

    Krukovich, M. G.

    2004-01-01

    Simulation of the nitriding process makes it possible to solve many practical problems of process control, prediction of results, and development of new treatment modes and treated materials. The presented classification systematizes nitriding processes and processes based on nitriding, enables consideration of the theory and practice of an individual process in interrelation with other phenomena, outlines ways for intensification of various process variants, and gives grounds for development of recommendations for controlling the structure and properties of the obtained layers. The general rules for conducting the process and formation of phases in the layer and properties of the treated surfaces are used to create a prediction computational model based on analytical, numerical, and empirical approaches.

  1. Stoichiometric carbon nitride synthesized by ion beam sputtering and post nitrogen ion implantation

    International Nuclear Information System (INIS)

    Valizadeh, R.; Colligon, J.S.; Katardiev, I.V.; Faunce, C.A.; Donnelly, S.E.

    1998-01-01

    Full text: Carbon nitride films have been deposited on Si (100) by ion beam sputtering a vitreous graphite target with nitrogen and argon ions with and without concurrent N2 ion bombardment at room temperature. The sputtering beam energy was 1000 eV and the assisted beam energy was 300 eV with ion / atom arrival ratio ranging from 0.5 to 5. The carbon nitride films were deposited both as single layer directly on silicon substrate and as multilayer between two layers of stoichiometric amorphous silicon nitride and polycrystalline titanium nitride. The deposited films were implanted ex-situ with 30 keV nitrogen ions with various doses ranging from 1E17 to 4E17 ions.cm -2 and 2 GeV xenon ion with a dose of 1E12 ions.cm -2 . The nitrogen concentration of the films was measured with Rutherford Backscattering (RBS), Secondary Neutral Mass Spectrometry (SNMS) and Parallel Electron Energy Loss Spectroscopy (PEELS). The nitrogen concentration for as deposited sample was 34 at% and stoichiometric carbon nitride C 3 N 4 was achieved by post nitrogen implantation of the multi-layered films. Post bombardment of single layer carbon nitride films lead to reduction in the total nitrogen concentration. Carbon K edge structure obtained from PEELS analysis suggested that the amorphous C 3 N 4 matrix was predominantly sp 2 bonded. This was confirmed by Fourier Transforrn Infra-Red Spectroscopy (FTIR) analysis of the single CN layer which showed the nitrogen was mostly bonded with carbon in nitrile (C≡N) and imine (C=N) groups. The microstructure of the film was determined by Transmission Electron Microscopy (TEM) which indicated that the films were amorphous

  2. Nitridation of si using mechano-fusion method

    International Nuclear Information System (INIS)

    Li, Z. L.; Calka, A.; Williams, J. S.

    1996-01-01

    Full text: It has been found that silicon nitride (Si 3 N 4 ) can be formed by ball milling of Si in ammonia. However only small fraction of Si can be transformed into 1 Si 3 N 4 . The major milling effect is the formation of poly/nanocrystalline silicon. At this stage of research it is difficult to answer the question why ball milling causes only limited formation of Si 3 N 4 . It is due to little understanding of 1 processes occurring during milling. Therefore, the purpose of this work was to study nitridation reaction during milling of Si in ammonia. In particular the 1 effect of milling conditions such as milling energies, atmosphere and a form of starting material was studied. The micro/macrostructural development during milling and subsequent annealing was studied using x-ray diffractometry, thermal analysis, elemental analysis measurement. It was found that the transformed fraction of Si 3 N 4 compound is strongly dependent on milling energies and milling atmosphere

  3. Fabrication of silicon condenser microphones using single wafer technology

    NARCIS (Netherlands)

    Scheeper, P.R.; van der Donk, A.G.H.; Olthuis, Wouter; Bergveld, Piet

    1992-01-01

    A condenser microphone design that can be fabricated using the sacrificial layer technique is proposed and tested. The microphone backplate is a 1-¿m plasma-enhanced chemical-vapor-deposited (PECVD) silicon nitride film with a high density of acoustic holes (120-525 holes/mm2), covered with a thin

  4. Sintering of nano crystalline o silicon carbide doping with

    Indian Academy of Sciences (India)

    Sinterable silicon carbide powders were prepared by attrition milling and chemical processing of an acheson type -SiC. Pressureless sintering of these powders was achieved by addition of aluminium nitride together with carbon. Nearly 99% sintered density was obtained. The mechanism of sintering was studied by ...

  5. SiNTO EWT silicon solar cells

    OpenAIRE

    Fallisch, A.; Keding, R.; Kästner, G.; Bartsch, J.; Werner, S.; Stüwe, D.; Specht, J.; Preu, R.; Biro, D.

    2010-01-01

    In this work we combine the SiNTO cell process with the EWT cell concept. All masking steps are performed by inkjet printing technology. The via-holes and laser-fired contacts are created by high-speed laser drilling. A new polishing process, which is suitable for inkjet masking, to pattern the interdigitated grid on the rear side is developed. For passivation purposes a thermal silicon oxide is used for the rear surface and a silicon nitride antireflection coating for the front surface. An e...

  6. Detection of chlorinated aromatic compounds

    Science.gov (United States)

    Ekechukwu, A.A.

    1996-02-06

    A method for making a composition for measuring the concentration of chlorinated aromatic compounds in aqueous fluids, and an optical probe for use with the method are disclosed. The composition comprises a hydrophobic polymer matrix, preferably polyamide, with a fluorescent indicator uniformly dispersed therein. The indicator fluoresces in the presence of the chlorinated aromatic compounds with an intensity dependent on the concentration of these compounds in the fluid of interest, such as 8-amino-2-naphthalene sulfonate. The probe includes a hollow cylindrical housing that contains the composition in its distal end. The probe admits an aqueous fluid to the probe interior for exposure to the composition. An optical fiber transmits excitation light from a remote source to the composition while the indicator reacts with chlorinated aromatic compounds present in the fluid. The resulting fluorescence light signal is reflected to a second optical fiber that transmits the light to a spectrophotometer for analysis. 5 figs.

  7. Effects of Chlorine on Enterovirus RNA Degradation

    Science.gov (United States)

    The primary mechanism of disinfection of waterborne pathogens by chlorine has always been believed to be due to the alteration of proteins by free chlorine and subsequent disruption of their biological structure.

  8. Kinetics of molybdenum and chlorine interaction

    International Nuclear Information System (INIS)

    Zelikman, A.N.; Nazarov, Yu.N.; Sarkarov, T.Eh.; Tulyakov, N.V.

    1977-01-01

    The kinetics is studied of molybdenite chlorination with gaseous chlorine. The time dependences of the depth and degree of molybdenite chlorination are given along with the dependence on chlorine concentration of molybdenite chlorination rate. Active interaction is shown to take place at 450-470 deg C. At 350-435 deg C, chlorination occurs in the kinetic range, the apparent activation energy being equal to 22.2 kcal/mole and the order of reaction by chlorine to 0.77. At 435-610 deg C, the process takes place in the diffusion range and is restricted by dissipation of the reaction products (activation energy - 4.05 kcal/mole; order of reaction by chlorine - 0.6)

  9. Formation of aryl-chlorinated aromatic acids and precursors for chloroform in chlorination of humic acid

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Leer, E.W.B. de; Galan, L.

    1985-01-01

    The formation of chloroform when humic substances are chlorinated is well known. Other chlorinated products that may be formed are chloral, di- and trichloroacetic acid, chlorinated C-4 diacids, and α-chlorinated aliphatic acids. Several of these compounds are formed in molar yields comparable

  10. Precipitation of metal nitrides from chloride melts

    International Nuclear Information System (INIS)

    Slater, S.A.; Miller, W.E.; Willit, J.L.

    1996-01-01

    Precipitation of actinides, lanthanides, and fission products as nitrides from molten chloride melts is being investigated for use as a final cleanup step in treating radioactive salt wastes generated by electrometallurgical processing of spent nuclear fuel. The radioactive components (eg, fission products) need to be removed to reduce the volume of high-level waste that requires disposal. To extract the fission products from the salt, a nitride precipitation process is being developed. The salt waste is first contacted with a molten metal; after equilibrium is reached, a nitride is added to the metal phase. The insoluble nitrides can be recovered and converted to a borosilicate glass after air oxidation. For a bench-scale experimental setup, a crucible was designed to contact the salt and metal phases. Solubility tests were performed with candidate nitrides and metal nitrides for which there are no solubility data. Experiments were performed to assess feasibility of precipitation of metal nitrides from chloride melts

  11. Silicon detectors

    International Nuclear Information System (INIS)

    Klanner, R.

    1984-08-01

    The status and recent progress of silicon detectors for high energy physics is reviewed. Emphasis is put on detectors with high spatial resolution and the use of silicon detectors in calorimeters. (orig.)

  12. Direct Chlorination of Zircon Sand

    International Nuclear Information System (INIS)

    Dwiretnani Sudjoko; Budi Sulistyo; Pristi Hartati; Sunardjo

    2002-01-01

    It was investigated the direct chlorination of zircon sand in a unit chlorination equipment. The process was in semi batch. The product gas was scrubbed in aqueous NaOH. It was search the influence of time, ratio of reactant and size of particle sand to the concentration of Zr and Si in the product. From these research it was found that as the times, ratio of reactant increased, the concentration of Zr increased, but the concentration of Si decreased, while as grain size of zircon sand decreased the concentration of Zr decreased, but the concentration of Si increased. (author)

  13. Fluorescent lighting with aluminum nitride phosphors

    Science.gov (United States)

    Cherepy, Nerine J.; Payne, Stephen A.; Seeley, Zachary M.; Srivastava, Alok M.

    2016-05-10

    A fluorescent lamp includes a glass envelope; at least two electrodes connected to the glass envelope; mercury vapor and an inert gas within the glass envelope; and a phosphor within the glass envelope, wherein the phosphor blend includes aluminum nitride. The phosphor may be a wurtzite (hexagonal) crystalline structure Al.sub.(1-x)M.sub.xN phosphor, where M may be drawn from beryllium, magnesium, calcium, strontium, barium, zinc, scandium, yttrium, lanthanum, cerium, praseodymium, europium, gadolinium, terbium, ytterbium, bismuth, manganese, silicon, germanium, tin, boron, or gallium is synthesized to include dopants to control its luminescence under ultraviolet excitation. The disclosed Al.sub.(1-x)M.sub.xN:Mn phosphor provides bright orange-red emission, comparable in efficiency and spectrum to that of the standard orange-red phosphor used in fluorescent lighting, Y.sub.2O.sub.3:Eu. Furthermore, it offers excellent lumen maintenance in a fluorescent lamp, and does not utilize "critical rare earths," minimizing sensitivity to fluctuating market prices for the rare earth elements.

  14. Aluminum nitride and nanodiamond thin film microstructures

    Energy Technology Data Exchange (ETDEWEB)

    Knoebber, Fabian; Bludau, Oliver; Roehlig, Claus-Christian; Williams, Oliver; Sah, Ram Ekwal; Kirste, Lutz; Cimalla, Volker; Lebedev, Vadim; Nebel, Christoph; Ambacher, Oliver [Fraunhofer-Institute for Applied Solid State Physics, Freiburg (Germany)

    2010-07-01

    In this work, aluminum nitride (AlN) and nanocrystalline diamond (NCD) thin film microstructures have been developed. Freestanding NCD membranes were coated with a piezoelectrical AlN layer in order to build tunable micro-lens arrays. For the evaluation of the single material quality, AlN and NCD thin films on silicon substrates were fabricated using RF magnetron sputtering and microwave chemical vapor deposition techniques, respectively. The crystal quality of AlN was investigated by X-ray diffraction. The piezoelectric constant d{sub 33} was determined by scanning laser vibrometry. The NCD thin films were optimized with respect to surface roughness, mechanical stability, intrinsic stress and transparency. To determine the mechanical properties of the materials, both, micromechanical resonator and membrane structures were fabricated and measured by magnetomotive resonant frequency spectroscopy and bulging experiments, respectively. Finally, the behavior of AlN/NCD heterostructures was modeled using the finite element method and the first structures were characterized by piezoelectrical measurements.

  15. Facile fabrication of boron nitride nanosheets-amorphous carbon hybrid film for optoelectronic applications

    KAUST Repository

    Wan, Shanhong

    2015-01-01

    A novel boron nitride nanosheets (BNNSs)-amorphous carbon (a-C) hybrid film has been deposited successfully on silicon substrates by simultaneous electrochemical deposition, and showed a good integrity of this B-C-N composite film by the interfacial bonding. This synthesis can potentially provide the facile control of the B-C-N composite film for the potential optoelectronic devices. This journal is

  16. Detection of chlorine in water

    Czech Academy of Sciences Publication Activity Database

    Kašík, Ivan; Mrázek, Jan; Podrazký, Ondřej; Seidl, Miroslav; Aubrecht, Jan; Tobiška, Petr; Pospíšilová, Marie; Matějec, Vlastimil; Kovács, B.; Markovics, A.; Szili, M.

    2009-01-01

    Roč. 139, č. 1 (2009), s. 139-142 ISSN 0925-4005 R&D Projects: GA MŠk(CZ) LC06034; GA ČR(CZ) GA102/05/0948 Institutional research plan: CEZ:AV0Z20670512 Keywords : optical fiber sensor * chlorine Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 3.083, year: 2009

  17. Mechanisms and characteristics of silicon combustion in nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Mukasian, A.S.; Martynenko, V.M.; Merzhanov, A.G.; Borovinskaia, I.P.; Blinov, M.IU.

    1986-10-01

    An experimental study is made of the principal characteristics of combustion in the system silicon-nitrogen associated with phase transitions of the first kind (silicon melting and silicon nitride dissociation). Concepts of the combustion mechanism are developed on the basis of elementary models of combustion of the second kind and filtering combustion theory. In particular, it is shown that, in the pressure range studied (10-20 MPa), filtering does not limit the combustion process. Details of the experimental procedure and results are presented. 22 references.

  18. Low-loss, submicron chalcogenide integrated photonics with chlorine plasma etching

    Energy Technology Data Exchange (ETDEWEB)

    Chiles, Jeff; Malinowski, Marcin; Rao, Ashutosh [CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816 (United States); Novak, Spencer; Richardson, Kathleen [CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816 (United States); Department of Materials Science and Engineering, COMSET, Clemson University, Clemson, South Carolina 29634 (United States); Fathpour, Sasan, E-mail: fathpour@creol.ucf.edu [CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816 (United States); Department of Electrical Engineering and Computer Science, University of Central Florida, Orlando, Florida 32816 (United States)

    2015-03-16

    A chlorine plasma etching-based method for the fabrication of high-performance chalcogenide-based integrated photonics on silicon substrates is presented. By optimizing the etching conditions, chlorine plasma is employed to produce extremely low-roughness etched sidewalls on waveguides with minimal penalty to propagation loss. Using this fabrication method, microring resonators with record-high intrinsic Q-factors as high as 450 000 and a corresponding propagation loss as low as 0.42 dB/cm are demonstrated in submicron chalcogenide waveguides. Furthermore, the developed chlorine plasma etching process is utilized to demonstrate fiber-to-waveguide grating couplers in chalcogenide photonics with high power coupling efficiency of 37% for transverse-electric polarized modes.

  19. Low-loss, submicron chalcogenide integrated photonics with chlorine plasma etching

    International Nuclear Information System (INIS)

    Chiles, Jeff; Malinowski, Marcin; Rao, Ashutosh; Novak, Spencer; Richardson, Kathleen; Fathpour, Sasan

    2015-01-01

    A chlorine plasma etching-based method for the fabrication of high-performance chalcogenide-based integrated photonics on silicon substrates is presented. By optimizing the etching conditions, chlorine plasma is employed to produce extremely low-roughness etched sidewalls on waveguides with minimal penalty to propagation loss. Using this fabrication method, microring resonators with record-high intrinsic Q-factors as high as 450 000 and a corresponding propagation loss as low as 0.42 dB/cm are demonstrated in submicron chalcogenide waveguides. Furthermore, the developed chlorine plasma etching process is utilized to demonstrate fiber-to-waveguide grating couplers in chalcogenide photonics with high power coupling efficiency of 37% for transverse-electric polarized modes

  20. Emerging heterogeneous integrated photonic platforms on silicon

    Directory of Open Access Journals (Sweden)

    Fathpour Sasan

    2015-05-01

    Full Text Available Silicon photonics has been established as a mature and promising technology for optoelectronic integrated circuits, mostly based on the silicon-on-insulator (SOI waveguide platform. However, not all optical functionalities can be satisfactorily achieved merely based on silicon, in general, and on the SOI platform, in particular. Long-known shortcomings of silicon-based integrated photonics are optical absorption (in the telecommunication wavelengths and feasibility of electrically-injected lasers (at least at room temperature. More recently, high two-photon and free-carrier absorptions required at high optical intensities for third-order optical nonlinear effects, inherent lack of second-order optical nonlinearity, low extinction ratio of modulators based on the free-carrier plasma effect, and the loss of the buried oxide layer of the SOI waveguides at mid-infrared wavelengths have been recognized as other shortcomings. Accordingly, several novel waveguide platforms have been developing to address these shortcomings of the SOI platform. Most of these emerging platforms are based on heterogeneous integration of other material systems on silicon substrates, and in some cases silicon is integrated on other substrates. Germanium and its binary alloys with silicon, III–V compound semiconductors, silicon nitride, tantalum pentoxide and other high-index dielectric or glass materials, as well as lithium niobate are some of the materials heterogeneously integrated on silicon substrates. The materials are typically integrated by a variety of epitaxial growth, bonding, ion implantation and slicing, etch back, spin-on-glass or other techniques. These wide range of efforts are reviewed here holistically to stress that there is no pure silicon or even group IV photonics per se. Rather, the future of the field of integrated photonics appears to be one of heterogenization, where a variety of different materials and waveguide platforms will be used for

  1. Chlorination Revisited: Does Cl- Serve as a Catalyst in the Chlorination of Phenols?

    Science.gov (United States)

    Lau, Stephanie S; Abraham, Sonali M; Roberts, A Lynn

    2016-12-20

    The aqueous chlorination of (chloro)phenols is one of the best-studied reactions in the environmental literature. Previous researchers have attributed these reactions to two chlorine species: HOCl (at circum-neutral and high pH) and H 2 OCl + (at low pH). In this study, we seek to examine the roles that two largely overlooked chlorine species, Cl 2 and Cl 2 O, may play in the chlorination of (chloro)phenols. Solution pH, chloride concentration, and chlorine dose were systematically varied in order to assess the importance of different chlorine species as chlorinating agents. Our findings indicate that chlorination rates at pH pH 6.0 and a chlorine dose representative of drinking water treatment, Cl 2 O is predicted to have at best a minor impact on chlorination reactions, whereas Cl 2 may contribute more than 80% to the overall chlorination rate depending on the (chloro)phenol identity and chloride concentration. While it is not possible to preclude H 2 OCl + as a chlorinating agent, we were able to model our low-pH data by considering Cl 2 only. Even traces of chloride can generate sufficient Cl 2 to influence chlorination kinetics, highlighting the role of chloride as a catalyst in chlorination reactions.

  2. Microdefects in neutron-transmutationaly doped silicon

    International Nuclear Information System (INIS)

    Vysotskaya, V.V.; Gorin, S.N.; Gres'kov, I.M.; Sobolev, N.A.; Shek, E.I.

    1988-01-01

    Using the method of X-ray topography and high-voltage electron microscopy, the nature of microdefects and character of their changes in neutron-transmutationaly doped silicon depending on the sample prehistory and heat treatment (HT) conditions are refined. It is shown that the microstructure of neutron-transmutationaly doped dislocation-free silicon crystals depends on conditions of ingot growth and post-radiation annealing environment. Annealing in chlorine-containing atmosphere removes microdefects (MD), although in vacuum, argon or air growing MD are preserved and new MD are formed

  3. Microdefects in neutron-transmutationaly doped silicon

    Energy Technology Data Exchange (ETDEWEB)

    Vysotskaya, V V; Gorin, S N; Gres' kov, I M; Sobolev, N A; Shek, E I

    1988-03-01

    Using the method of X-ray topography and high-voltage electron microscopy, the nature of microdefects and character of their changes in neutron-transmutationaly doped silicon depending on the sample prehistory and heat treatment (HT) conditions are refined. It is shown that the microstructure of neutron-transmutationaly doped dislocation-free silicon crystals depends on conditions of ingot growth and post-radiation annealing environment. Annealing in chlorine-containing atmosphere removes microdefects (MD), although in vacuum, argon or air growing MD are preserved and new MD are formed.

  4. Effect of Variation of Silicon Nitride Passivation Layer on Electron Irradiated Aluminum Gallium Nitride/Gallium Nitride HEMT Structures

    Science.gov (United States)

    2014-06-19

    family have (0001) interfaces which bear a surface charge σ0 that results from the polarizations of the two alloys at the interface...function of the Al content of the AlGaN barrier, as well as its thickness (Kocan, 2003; Lenka and Panda , 2011). In my dissertation, the surface...incorporation.” Applied Physics Letters, 71 (1997): 1359. Lenka, T. R., and Panda , A. K.. “Effect of structural parameters of 2DEG and C~V

  5. Ion nitridation - physical and technological aspects

    International Nuclear Information System (INIS)

    Elbern, A.W.

    1980-01-01

    Ion nitridation, is a technique which allows the formation of a controlled thickness of nitrides in the surface of the material, using this material as the cathode in a low pressure glow discharge, which presents many advantages over the conventional method. A brief review of the ion nitriding technique, the physical fenomena involved, and we discuss technological aspects of this method, are presented. (Author) [pt

  6. Aluminum Nitride Micro-Channels Grown via Metal Organic Vapor Phase Epitaxy for MEMs Applications

    Energy Technology Data Exchange (ETDEWEB)

    Rodak, L.E.; Kuchibhatla, S.; Famouri, P.; Ting, L.; Korakakis, D.

    2008-01-01

    Aluminum nitride (AlN) is a promising material for a number of applications due to its temperature and chemical stability. Furthermore, AlN maintains its piezoelectric properties at higher temperatures than more commonly used materials, such as Lead Zirconate Titanate (PZT) [1, 2], making AlN attractive for high temperature micro and nanoelectromechanical (MEMs and NEMs) applications including, but not limited to, high temperature sensors and actuators, micro-channels for fuel cell applications, and micromechanical resonators. This work presents a novel AlN micro-channel fabrication technique using Metal Organic Vapor Phase Epitaxy (MOVPE). AlN easily nucleates on dielectric surfaces due to the large sticking coefficient and short diffusion length of the aluminum species resulting in a high quality polycrystalline growth on typical mask materials, such as silicon dioxide and silicon nitride [3,4]. The fabrication process introduced involves partially masking a substrate with a silicon dioxide striped pattern and then growing AlN via MOVPE simultaneously on the dielectric mask and exposed substrate. A buffered oxide etch is then used to remove the underlying silicon dioxide and leave a free standing AlN micro-channel. The width of the channel has been varied from 5 ìm to 110 ìm and the height of the air gap from 130 nm to 800 nm indicating the stability of the structure. Furthermore, this versatile process has been performed on (111) silicon, c-plane sapphire, and gallium nitride epilayers on sapphire substrates. Reflection High Energy Electron Diffraction (RHEED), Atomic Force Microscopy (AFM), and Raman measurements have been taken on channels grown on each substrate and indicate that the substrate is influencing the growth of the AlN micro-channels on the SiO2 sacrificial layer.

  7. Topotactic synthesis of vanadium nitride solid foams

    International Nuclear Information System (INIS)

    Oyama, S.T.; Kapoor, R.; Oyama, H.T.; Hofmann, D.J.; Matijevic, E.

    1993-01-01

    Vanadium nitride has been synthesized with a surface area of 120 m 2 g -1 by temperature programmed nitridation of a foam-like vanadium oxide (35 m 2 g -1 ), precipitated from vanadate solutions. The nitridation reaction was established to be topotactic and pseudomorphous by x-ray powder diffraction and scanning electron microscopy. The crystallographic relationship between the nitride and oxide was {200}//{001}. The effect of precursor geometry on the product size and shape was investigated by employing vanadium oxide solids of different morphologies

  8. Microhardness and microplasticity of zirconium nitride

    International Nuclear Information System (INIS)

    Neshpor, V.S.; Eron'yan, M.A.; Petrov, A.N.; Kravchik, A.E.

    1978-01-01

    To experimentally check the concentration dependence of microhardness of 4 group nitrides, microhardness of zirconium nitride compact samples was measured. The samples were obtained either by bulk saturation of zirconium iodide plates or by chemical precipitation from gas. As nitrogen content decreased within the limits of homogeneity of zirconium nitride samples where the concentration of admixed oxygen was low, the microhardness grew from 1500+-100 kg/mm 2 for ZrNsub(1.0) to 27000+-100 kg/mm 2 for ZrNsub(0.78). Microplasticity of zirconium nitride (resistance to fracture) decreased, as the concentration of nitrogen vacancies was growing

  9. Chemical interaction silicon nitride ceramics and iron alloys

    Directory of Open Access Journals (Sweden)

    Oliveira, F. J.

    2000-12-01

    Full Text Available Metal/ceramic diffusion experiments are helpful to study bonding mechanisms or the effect of metal composition on the chemical wear of ceramic cutting tools. The reaction kinetics of Fe alloys/Si3 N4 ceramic diffusion couples was investigated in the temperature range 1050ºC-1250ºC, for 0.5h to 80h, under inert atmosphere. Optical microscopy, SEM and EPMA were carried out in cross sections of the reacted pairs. Si3N4 decomposes into Si and N that dissolve and diffuse through the metal. Both the diffusion zone on the metal side and the reaction zone on the ceramic side obey parabolic growth laws of time, with activation energies in the range Q=310-460kJmol-1. The amount of dissolved Si, the length of the diffusion zone and thus the reactivity of the ceramic increase as the alloy carbon content decreases. Due to Si accumulation, the α-Fe solid solution is stabilised at the reaction temperature and a steep decrease in the Si concentration is observed beyond the diffusion zone. The reinforcement of the Si3N4 composites with A12O3 platelets enhances the chemical resistance of the ceramic due to the inertness of this oxide and to the partial crystallisation of the intergranular phase. Other dispersoids such as HfN, BN and TiN do not improve the chemical resistance of the matrix by iron attack.

    Los experimentos de difusión metal/cerámica permiten estudiar mecanismos de unión y analizar el efecto de la composición del metal en el desgaste químico de herramientas de corte cerámicas. En este trabajo se investigó la cinética de reacción en pares de difusión aleaciones de Fe/Si3N4 a temperaturas entre 1050ºC-1250ºC, tiempos entre 0.5h a 80h, en atmósfera inerte. Las secciones transversales de los pares de difusión se analizaron mediante microscopía óptica, SEM y microsonda electrónica. El Si3N4 se descompone en Si y N que se disuelven y difunden en el metal. Tanto la zona de difusión en el metal como la zona de reacción en la cerámica obedecen una ley parabólica de crecimiento, con energías de activación de 310-460 KJ.mol-1. La cantidad de Si disuelto, el tamaño de la zona de difusión y, por lo tanto, la reactividad de la cerámica aumenta al diminuir el contenido de carbón de la aleación. Debido a la acumulación de Si, la solución sólida de α-Fe se estabiliza a la temperatura de reacción, y se observa un descenso significativo en la concentración de Si más allá de la zona de difusión. El reforzamiento del Si3N4 con plaquetas de Al2O3 aumenta la resistencia química del Si3N4 debido a la inercia de este oxido y a la cristalización parcial de la fase intergranular. La incorporación de HfN, BN y TiN no mejoran la resistencia química de la matriz al ataque por Fe.

  10. Quantum Cavity Optomechanics with Phononic Bandgap Shielded Silicon Nitride Membranes

    DEFF Research Database (Denmark)

    Nielsen, William Hvidtfelt Padkær

    two highly reflective mirrors, all of which are embedded in a helium flowcryostat. In order to reach truly quantum territory, severe shielding of the membranefrom the environment is required, as well as meticulous concern for auxiliarysources of noise, both from the laser and mirrors used.The purpose...... of this thesis is to document the development of the experimentfrom its initial stages to its final quantum enabled incarnation, as well as to providethe necessary theoretical machinery to interpret the experimental results. A strongemphasis is placed on the unique challenges posed by our unique monolithic...

  11. Electrical and optical properties of silicon-doped gallium nitride

    Indian Academy of Sciences (India)

    Si-doped GaN films in polycrystalline form were deposited on quartz substrates at deposition temperatures ranging from 300–623 K using r.f. sputtering technique. Electrical, optical and microstructural properties were studied for these films. It was observed that films deposited at room temperature contained mainly ...

  12. Dissolution behaviour of silicon nitride coatings for joint replacements

    Energy Technology Data Exchange (ETDEWEB)

    Pettersson, Maria [Materials in Medicine Group, Div. of Applied Materials Science, Dept. of Engineering Sciences, Uppsala University, Uppsala (Sweden); Bryant, Michael [Institute of Functional Surfaces (iFS), School of Mechanical Engineering, University of Leeds, Leeds (United Kingdom); Schmidt, Susann [Thin Film Physics, Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping (Sweden); Engqvist, Håkan [Materials in Medicine Group, Div. of Applied Materials Science, Dept. of Engineering Sciences, Uppsala University, Uppsala (Sweden); Hall, Richard M. [Institute of Medical and Biological Engineering (iMBE), School of Mechanical Engineering, University of Leeds, Leeds (United Kingdom); Neville, Anne [Institute of Functional Surfaces (iFS), School of Mechanical Engineering, University of Leeds, Leeds (United Kingdom); Persson, Cecilia, E-mail: cecilia.persson@angstrom.uu.se [Materials in Medicine Group, Div. of Applied Materials Science, Dept. of Engineering Sciences, Uppsala University, Uppsala (Sweden)

    2016-05-01

    In this study, the dissolution rate of SiN{sub x} coatings was investigated as a function of coating composition, in comparison to a cobalt chromium molybdenum alloy (CoCrMo) reference. SiN{sub x} coatings with N/Si ratios of 0.3, 0.8 and 1.1 were investigated. Electrochemical measurements were complemented with solution (inductively coupled plasma techniques) and surface analysis (vertical scanning interferometry and x-ray photoelectron spectroscopy). The dissolution rate of the SiN{sub x} coatings was evaluated to 0.2–1.4 nm/day, with a trend of lower dissolution rate with higher N/Si atomic ratio in the coating. The dissolution rates of the coatings were similar to or lower than that of CoCrMo (0.7–1.2 nm/day). The highest nitrogen containing coating showed mainly Si–N bonds in the bulk as well as at the surface and in the dissolution area. The lower nitrogen containing coatings showed Si–N and/or Si–Si bonds in the bulk and an increased formation of Si–O bonds at the surface as well as in the dissolution area. The SiN{sub x} coatings reduced the metal ion release from the substrate. The possibility to tune the dissolution rate and the ability to prevent release of metal ions encourage further studies on SiN{sub x} coatings for joint replacements. - Graphical abstract: Dissolution rates of SiN{sub 0.3}, SiN{sub 0.8}, and SiN{sub 1.1} coatings on CoCrMo compared to uncoated CoCrMo. Dissolution rates were obtained from i) electrochemical measurements of I{sub corr}, ii) the step height between covered and solution-exposed surfaces, measured using VSI, and iii) the ion concentration in the solution, measured with ICP. - Highlights: • The dissolution of SiN{sub x} coatings was investigated in comparison to (bulk) CoCrMo. • The coatings gave a lower or similar dissolution rate to CoCrMo, of 0.2–1.2 nm/day. • An increased nitrogen content in the coatings gave lower dissolution rates. • SiN{sub x} coatings on CoCrMo reduced the metal ion release by two orders of magnitude.

  13. Water Chlorination for human consumption

    International Nuclear Information System (INIS)

    Innocenti, A.; Giacosa, D.; Segatori, M.

    1999-01-01

    Beginning from this issue, an initiative of Federgasacqua (Federal association dealing with the gas and the water) takes place through the activities of the Task Forces Water Quality Control and Materials and Processes, which aim is to offer to the water industry operators and updated information concerning some main subjects, emphasizing in particular the technical and management applied topics. The paper deals with the chlorination processes in drinking water treatment. An overview of the italian situation is presented, concerning disinfection as well as other oxidation processes, together with an historical background on chlorination. Concerning the applications, the chemical technologies and the main processes, the disinfectant effectiveness and the byproducts formation have been described. Further, the regulations in force have been reported and discussed on national and international bases [it

  14. The effect of chlorine and combined chlorine/UV treatment on coliphages in drinking water disinfection.

    Science.gov (United States)

    Zyara, Alyaa M; Torvinen, Eila; Veijalainen, Anna-Maria; Heinonen-Tanski, Helvi

    2016-08-01

    Chlorine disinfection is a globally used method to ensure the safety of drinking water. However, it has not always been successful against viruses and, therefore, it is important to find new methods to disinfect water. Seventeen different coliphages were isolated from the treated municipal wastewater. These coliphages and MS2 were treated with different dosages of chlorine in drinking water, and a combined chlorine/ultraviolet irradiation treatment for the chlorine-resistant coliphages. Chlorine disinfection with 0.3-0.5 mg/L total chlorine (free Cl-dosage 0.12-0.21 mg/L) for 10 min achieved 2.5-5.7 Log10-reductions for 11 sensitive coliphages. The six most resistant coliphages showed no reduction with these chlorine concentrations. MS2 was intermediate in chlorine resistance, and thus it is not a good indicator for viruses in chlorine disinfection. In the combined treatment total chlorine of 0.05-0.25 mg/L (free Cl-dosage 0.02-0.08 mg/L) and ultraviolet irradiation (14-22 mWs/cm(2)) were more effective than chlorine alone, and 3-5 Log10-reductions were achieved for the chlorine-resistant strains. The chlorination efficiency could be increased by higher dosages and longer contact times, but this could increase the formation of disinfection by-products. Therefore, the combination treatment is a recommended disinfection method.

  15. Metabolic fate of chlorinated paraffins

    International Nuclear Information System (INIS)

    Darnerud, P.O.; Biessmann, A.; Brandt, I.

    1982-01-01

    The disposition of three [1- 14 C]-chlorododecanes (MCDD, PCDD I and PCDD II; 17.4%, 55.9%, and 68.5% chlorination) was studied in C57Bl mice. [1- 14 C]-lauric acid (LA) was studied as reference compound. Fifty-two percent (MCDD), 32% (PCDD I), and 8% (PCDD II) of the radioactive doses were exhaled as 14 CO 2 during 12 h after i.v. injection. Similar results were obtained after p.o. administration. In addition to a marked labelling of the liver and fat, the distribution patterns observed at 24 h after administration revealed an uptake of radioactivity in tissues with high cell turnover/high metabolic activity, e.g., intestinal mucosa, bone marrow, salivary glands and thymus. The concentration of radioactivity in these sites and the exhalation of 14 CO 2 , which were inverse to the degree of chlorination, indicate that the chloroalkanes are degraded to metabolites which can be utilized in the intermediary metabolism. A similar, although more pronounced, distribution pattern and 14 CO 2 -exhalation (70% of i.v. dose) was observed after LA administration. The long time retention of heptane-soluble radioactivity in liver and fat (indicating unmetabolized substance) increased with degree of chlorination. On the contrary, the administration of LA and the chlorododecanes MCDD and PCDD I, but not of PCDD II, resulted in a selective labelling of the central nervous system 30-60 days after injection. (orig.)

  16. Nitride alloy layer formation of duplex stainless steel using nitriding process

    Science.gov (United States)

    Maleque, M. A.; Lailatul, P. H.; Fathaen, A. A.; Norinsan, K.; Haider, J.

    2018-01-01

    Duplex stainless steel (DSS) shows a good corrosion resistance as well as the mechanical properties. However, DSS performance decrease as it works under aggressive environment and at high temperature. At the mentioned environment, the DSS become susceptible to wear failure. Surface modification is the favourable technique to widen the application of duplex stainless steel and improve the wear resistance and its hardness properties. Therefore, the main aim of this work is to nitride alloy layer on the surface of duplex stainless steel by the nitriding process temperature of 400°C and 450°C at different time and ammonia composition using a horizontal tube furnace. The scanning electron microscopy and x-ray diffraction analyzer are used to analyse the morphology, composition and the nitrided alloy layer for treated DSS. The micro hardnesss Vickers tester was used to measure hardness on cross-sectional area of nitrided DSS. After nitriding, it was observed that the hardness performance increased until 1100 Hv0.5kgf compared to substrate material of 250 Hv0.5kgf. The thickness layer of nitride alloy also increased from 5μm until 100μm due to diffusion of nitrogen on the surface of DSS. The x-ray diffraction results showed that the nitride layer consists of iron nitride, expanded austenite and chromium nitride. It can be concluded that nitride alloy layer can be produced via nitriding process using tube furnace with significant improvement of microstructural and hardness properties.

  17. Formation of aluminium nitride and segregation of Cu impurity atoms in aluminium implanted by high dose nitrogen ions

    International Nuclear Information System (INIS)

    Lin Chenglu; Hemment, P.L.F.; Li Jinhua; Zou Shichang

    1994-01-01

    Aluminium films with a thickness of 7000 A (containing 0.85% copper) were deposited on silicon substrates. 400 keV N 2 + or 350 keV N + ions were implanted into the aluminium films or at the interface between the aluminium and silicon, respectively. Automatic spreading resistance (ASR), Fourier transform infrared spectroscopy (FTIR) and Rutherford backscattering (RBS) and channelling were used to characterize the formation of aluminium nitride and the depth distribution of the Cu impurity in the aluminium films after ion implantation and post-annealing. The formation of a stoichiometric AlN layer with high resistance was evident from ASR, RBS analysis and FTIR measurements by the presence of the absorption band at 650 cm -1 . When the implanted nitrogen is near the interface between the aluminium and silicon, a multilayer structure can be obtained, which consists of aluminium, aluminium nitride and the silicon substrate. Cu, which is a background impurity in the deposited aluminium films, segregated into the synthesised aluminium nitride during high dose nitrogen ion implantation. This is due to irradiation-induced segregation during ion implantation. (orig.)

  18. Study on removing chlorin by conversion-aborption of chlorin resin

    International Nuclear Information System (INIS)

    Huang Yunbai; Zhao Jinfang; Tang Zhijuan; Huang Qijin; Deng Jianguo

    2012-01-01

    Theon version of chlorin resin and the reclamation of acid and uranium in converting solution were investigated. The results indicated the residual chlorin can meet the requirement after converting, acid and uranium in converting solution can be reclaimed. (authors)

  19. High-performance lithium battery anodes using silicon nanowires.

    Science.gov (United States)

    Chan, Candace K; Peng, Hailin; Liu, Gao; McIlwrath, Kevin; Zhang, Xiao Feng; Huggins, Robert A; Cui, Yi

    2008-01-01

    There is great interest in developing rechargeable lithium batteries with higher energy capacity and longer cycle life for applications in portable electronic devices, electric vehicles and implantable medical devices. Silicon is an attractive anode material for lithium batteries because it has a low discharge potential and the highest known theoretical charge capacity (4,200 mAh g(-1); ref. 2). Although this is more than ten times higher than existing graphite anodes and much larger than various nitride and oxide materials, silicon anodes have limited applications because silicon's volume changes by 400% upon insertion and extraction of lithium which results in pulverization and capacity fading. Here, we show that silicon nanowire battery electrodes circumvent these issues as they can accommodate large strain without pulverization, provide good electronic contact and conduction, and display short lithium insertion distances. We achieved the theoretical charge capacity for silicon anodes and maintained a discharge capacity close to 75% of this maximum, with little fading during cycling.

  20. Nonlinear Silicon Photonic Signal Processing Devices for Future Optical Networks

    Directory of Open Access Journals (Sweden)

    Cosimo Lacava

    2017-01-01

    Full Text Available In this paper, we present a review on silicon-based nonlinear devices for all optical nonlinear processing of complex telecommunication signals. We discuss some recent developments achieved by our research group, through extensive collaborations with academic partners across Europe, on optical signal processing using silicon-germanium and amorphous silicon based waveguides as well as novel materials such as silicon rich silicon nitride and tantalum pentoxide. We review the performance of four wave mixing wavelength conversion applied on complex signals such as Differential Phase Shift Keying (DPSK, Quadrature Phase Shift Keying (QPSK, 16-Quadrature Amplitude Modulation (QAM and 64-QAM that dramatically enhance the telecom signal spectral efficiency, paving the way to next generation terabit all-optical networks.

  1. Potassium chloride production by microcline chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Orosco, Pablo, E-mail: porosco@unsl.edu.ar [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina); Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, San Luis (Argentina); Ruiz, María del Carmen [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina)

    2015-08-10

    Highlights: • Use of chlorination for the KCl production. • The reagents used were microcline, hydromagnesite and chlorine. • Isothermal and non-isothermal assays were performed in Cl{sub 2}–N{sub 2} mixture. • The chlorination generated KCl at 700 °C. • The chlorination products promote KCl formation. - Abstract: The potassium chloride is one of the most important fertilizers used in agriculture. The current demand of this salt makes interesting the study of potassium chloride production from unconventional potassium resources. In this work the potassium chloride production by chlorination of microcline was investigated. The starting reagents were microcline, hydromagnesite and chlorine. Non-isothermal and isothermal chlorination assays were carried out in a thermogravimetric device adapted to work in corrosive atmospheres. The temperature effect on potassium extraction and the phase transformations produced during chlorination of microcline were studied. The reagents and reaction products were analyzed by X-ray fluorescence (XRF) and X-ray diffraction (XRD). The experimental results indicated that by chlorination of microcline an important extraction of potassium in the temperature range from 800 to 900 °C was produced. Moreover, at 800 °C the forsterite, enstatite and magnesium aluminate spinel phases were generated.

  2. Chlorine-36 investigations of salt lakes

    International Nuclear Information System (INIS)

    Chivas, A.R.; Kiss, E.

    1987-01-01

    The first chlorine-36 measurements are reported for surficial halite in lakes from a west-to-east traverse in Western Australia and from Lake Amadeus NT. Measurements of chlorine-36 were made using a 14 MV tandem accelerator. Isotopic chlorine ratios ranged from 8 to 53 x 10 exp-15, with no clear evidence for bomb-spike chlorine-36. The Western Australian samples have values close to secular equilibrium values for typical granite and groundwaters in this rock type. Studies are aimed at calculating the residence time of chloride in the surficial environment. 1 tab

  3. Localized surface phonon polariton resonances in polar gallium nitride

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Kaijun, E-mail: kfeng@nd.edu; Islam, S. M.; Verma, Jai; Hoffman, Anthony J. [Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Streyer, William; Wasserman, Daniel [Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801 (United States); Jena, Debdeep [Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); School of Electrical and Computer Engineering, Cornell University, Ithaca, New York 14850 (United States)

    2015-08-24

    We demonstrate the excitation of localized surface phonon polaritons in an array of sub-diffraction pucks fabricated in an epitaxial layer of gallium nitride (GaN) on a silicon carbide (SiC) substrate. The array is characterized via polarization- and angle-dependent reflection spectroscopy in the mid-infrared, and coupling to several localized modes is observed in the GaN Reststrahlen band (13.4–18.0 μm). The same structure is simulated using finite element methods and the charge density of the modes are studied; transverse dipole modes are identified for the transverse electric and magnetic polarizations and a quadrupole mode is identified for the transverse magnetic polarization. The measured mid-infrared spectrum agrees well with numerically simulated spectra. This work could enable optoelectronic structures and devices that support surface modes at mid- and far-infrared wavelengths.

  4. The initial growth stage in PVT growth of aluminum nitride

    Energy Technology Data Exchange (ETDEWEB)

    Heimann, P.; Epelbaum, B.M.; Bickermann, M.; Winnacker, A. [Department of Materials Science 6, University of Erlangen-Nuernberg, Martensstr. 7, 91058 Erlangen (Germany); Nagata, S. [Functional Materials Development Center, Research Laboratories, JFE Mineral Company, Ltd., 1, Niihama-cho, Chuou-ku, Chiba-shi, Chiba 260-0826 (Japan)

    2006-06-15

    The main issue in homoepitaxial growth of aluminum nitride (AlN) on native seed substrates is the formation of an aluminum oxynitride (AlON) layer at temperatures between 1850-1950 C leading to polycrystalline growth. On the contrary, heteroepitaxial growth of AlN on silicon carbide (SiC) is relatively easy to achieve due to natural formation of a thin molten layer of (Al{sub 2}OC{sub x}) on the seed surface and consequent growth of AlN via the molten buffer layer. Optimization of the seeding process can be achieved by use of ultra-pure starting material. Another critical issue of AlN growth on SiC is cracking of the grown layer upon cooling as a result of different thermal expansion coefficients. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Effective cleaning of hexagonal boron nitride for graphene devices.

    Science.gov (United States)

    Garcia, Andrei G F; Neumann, Michael; Amet, François; Williams, James R; Watanabe, Kenji; Taniguchi, Takashi; Goldhaber-Gordon, David

    2012-09-12

    Hexagonal boron nitride (h-BN) films have attracted considerable interest as substrates for graphene. ( Dean, C. R. et al. Nat. Nanotechnol. 2010 , 5 , 722 - 6 ; Wang, H. et al. Electron Device Lett. 2011 , 32 , 1209 - 1211 ; Sanchez-Yamagishi, J. et al. Phys. Rev. Lett. 2012 , 108 , 1 - 5 .) We study the presence of organic contaminants introduced by standard lithography and substrate transfer processing on h-BN films exfoliated on silicon oxide substrates. Exposure to photoresist processing adds a large broad luminescence peak to the Raman spectrum of the h-BN flake. This signal persists through typical furnace annealing recipes (Ar/H(2)). A recipe that successfully removes organic contaminants and results in clean h-BN flakes involves treatment in Ar/O(2) at 500 °C.

  6. Chlorination of cooling water: a source of chlorine-containing organic compounds with possible environmental significance

    International Nuclear Information System (INIS)

    Jolley, R.L.; Gehrs, C.W.; Pitt, W.W. Jr.

    1976-01-01

    Chlorination of cooling waters may be a source of environmentally significant pollutants. Many water-soluble chlorine-containing organic compounds of low volatility were found in a sample of cooling water chlorinated to a 2-mg/l chlorine concentration in the laboratory. The compounds were separated and detected using a coupled 36 Cl-tracer--high-resolution liquid chromatographic technique developed at the Oak Ridge National Laboratory for determination of chlorinated organics in process effluents. For a chlorination contact time of 75 min at 25 0 C, the yield of chlorine in the form of chloro-organics amounted to 0.78% of the chlorine dosage. It is estimated that the yield is about 0.5% under typical reaction conditions in the electric power plant cooling system chosen for study. Because chlorine is commonly used to remove slime films from the cooling systems of electric power plants, as a means of maintaining high operational efficiency, it is estimated that several hundred tons of chlorinated organics are produced annually in the nation by this antifoulant process. The chromatographic elution positions of some of the separated constituents correspond to those of compounds separated and partially identified from chlorinated sewage treatment plant effluents. The results of this study indicate the formation of chloro-organics during the chlorination of cooling waters should be thoroughly examined, particularly with respect to their identification and determination of possible toxicological properties

  7. Data for comparison of chlorine dioxide and chlorine disinfection power in a real dairy wastewater effluent

    Directory of Open Access Journals (Sweden)

    Maliheh Akhlaghi

    2018-06-01

    Full Text Available Disinfection of water refers to a special operation that is doing to kill or disable causative organisms (i.e. Pathogens and in particular, intestinal bacteria. The aim of this pilot study is comparison of disinfection power of Chlorine dioxide and chlorine in a real dairy wastewater effluent. In this regard, firstly prepared two 220-l tanks made of polyethylene as reaction tanks and filled by effluent of a dairy wastewater treatment plant. Both tanks were equipped with mechanical stirrer. Then a Diaphragm dosing pumps with the maximum capacity of 3.9 l per hour were used for the chlorine dioxide and chlorine (Calcium hypochlorite 0.5 up to 3 ppm injection. Residual level of Chlorine dioxide and Chlorine were measured by portable photometric method DT4B kit, Germany. Finally, the Multiple-Tube Fermentation, Brilliant Green Bile Broth (BGB and Eosin methylene blue Agar (EMB technique was used for microbial analysis and the results were reported as the most probable number index (MPN respectively. The data showed that the residual of chlorine dioxide could stood more active than residual of chlorine in the aqueous environment significantly. Therefore, Use of chlorine dioxide is more effective than chlorine for removal fecal and total coliform from dairy wastewater effluent. Keywords: Disinfection, Chlorine dioxide, Chlorine, Total coliform, Fecal coliform

  8. Method of preparation of uranium nitride

    Science.gov (United States)

    Kiplinger, Jaqueline Loetsch; Thomson, Robert Kenneth James

    2013-07-09

    Method for producing terminal uranium nitride complexes comprising providing a suitable starting material comprising uranium; oxidizing the starting material with a suitable oxidant to produce one or more uranium(IV)-azide complexes; and, sufficiently irradiating the uranium(IV)-azide complexes to produce the terminal uranium nitride complexes.

  9. Atomic Resolution Microscopy of Nitrides in Steel

    DEFF Research Database (Denmark)

    Danielsen, Hilmar Kjartansson

    2014-01-01

    MN and CrMN type nitride precipitates in 12%Cr steels have been investigated using atomic resolution microscopy. The MN type nitrides were observed to transform into CrMN both by composition and crystallography as Cr diffuses from the matrix into the MN precipitates. Thus a change from one...

  10. Investigation of Low-Cost Surface Processing Techniques for Large-Size Multicrystalline Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Yuang-Tung Cheng

    2010-01-01

    Full Text Available The subject of the present work is to develop a simple and effective method of enhancing conversion efficiency in large-size solar cells using multicrystalline silicon (mc-Si wafer. In this work, industrial-type mc-Si solar cells with area of 125×125 mm2 were acid etched to produce simultaneously POCl3 emitters and silicon nitride deposition by plasma-enhanced chemical vapor deposited (PECVD. The study of surface morphology and reflectivity of different mc-Si etched surfaces has also been discussed in this research. Using our optimal acid etching solution ratio, we are able to fabricate mc-Si solar cells of 16.34% conversion efficiency with double layers silicon nitride (Si3N4 coating. From our experiment, we find that depositing double layers silicon nitride coating on mc-Si solar cells can get the optimal performance parameters. Open circuit (Voc is 616 mV, short circuit current (Jsc is 34.1 mA/cm2, and minority carrier diffusion length is 474.16 μm. The isotropic texturing and silicon nitride layers coating approach contribute to lowering cost and achieving high efficiency in mass production.

  11. Alloy Effects on the Gas Nitriding Process

    Science.gov (United States)

    Yang, M.; Sisson, R. D.

    2014-12-01

    Alloy elements, such as Al, Cr, V, and Mo, have been used to improve the nitriding performance of steels. In the present work, plain carbon steel AISI 1045 and alloy steel AISI 4140 were selected to compare the nitriding effects of the alloying elements in AISI 4140. Fundamental analysis is carried out by using the "Lehrer-like" diagrams (alloy specific Lehrer diagram and nitriding potential versus nitrogen concentration diagram) and the compound layer growth model to simulate the gas nitriding process. With this method, the fundamental understanding for the alloy effect based on the thermodynamics and kinetics becomes possible. This new method paves the way for the development of new alloy for nitriding.

  12. The processing and potential applications of porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Syyuan Shieh.

    1992-07-01

    Stability of a cylindrical pore under the influence of surface energy is important for porous silicon (PS) processing in the integrated circuit industry. Once the zig-zag cylindrical pores of porous silicon or oxidized porous silicon (OPS) are unstable and breakup into rows of isolated spherical pores, oxidation of PS and densification/nitridation of OPS become difficult. Swing to difficulty transport of reactant gas (O{sub 2}, NH{sub 3}) or the trapped gas (for densification of OPS). A first order analysis of the stability of a cylindrical pore or cylinder is considered first. Growth of small sinusoidal perturbations by viscous flow or evaporation/condensation result in dependence of perturbation growth rate on perturbation wavelength. Rapid thermal oxidation (RTO) of porous silicon is proposed as an alternative for the tedious two-step 300 and 800C oxidation process. Transmission electron microscopy, energy dispersive spectroscopy ESCA are used for quality control. Also, rapid thermal nitridation of oxidized porous silicon in ammonia is proposed to enhance OPS resistance to HF solution. Pores breakup of OPS results in a trapped gas problem during densification. Wet helium is proposed as OPS densification ambient gas to shorten densification time. Finally, PS is proposed to be an extrinsic gettering center in silicon wafers. The suppression of oxidation-induced stacking faults is used to demonstrate the gettering ability. Possible mechanism is discussed.

  13. The processing and potential applications of porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Shieh, Syyuan [Univ. of California, Berkeley, CA (United States)

    1992-07-01

    Stability of a cylindrical pore under the influence of surface energy is important for porous silicon (PS) processing in the integrated circuit industry. Once the zig-zag cylindrical pores of porous silicon or oxidized porous silicon (OPS) are unstable and breakup into rows of isolated spherical pores, oxidation of PS and densification/nitridation of OPS become difficult. Swing to difficulty transport of reactant gas (O2, NH3) or the trapped gas (for densification of OPS). A first order analysis of the stability of a cylindrical pore or cylinder is considered first. Growth of small sinusoidal perturbations by viscous flow or evaporation/condensation result in dependence of perturbation growth rate on perturbation wavelength. Rapid thermal oxidation (RTO) of porous silicon is proposed as an alternative for the tedious two-step 300 and 800C oxidation process. Transmission electron microscopy, energy dispersive spectroscopy ESCA are used for quality control. Also, rapid thermal nitridation of oxidized porous silicon in ammonia is proposed to enhance OPS resistance to HF solution. Pores breakup of OPS results in a trapped gas problem during densification. Wet helium is proposed as OPS densification ambient gas to shorten densification time. Finally, PS is proposed to be an extrinsic gettering center in silicon wafers. The suppression of oxidation-induced stacking faults is used to demonstrate the gettering ability. Possible mechanism is discussed.

  14. Behavior of chlorine in lake water

    International Nuclear Information System (INIS)

    Sriraman, A.K.

    2006-01-01

    Water from monsoon fed Sagre lake is being used as a source of raw water for Tarapur Atomic Power Station (TAPS--1 and 2). The raw water from the lake is initially pumped to Sagre water treatment plant (SWTP) operated by Maharashtra Industrial Development Corporation (MIDC) from where, the processed water is sent to cater the needs of both the units of TAPS-1 and 2, townships of TAPS and MIDC, and the nearby villages. At the SWTP the raw water is treated with alum to remove the turbidity, filtered and chlorinated using bleaching powder. All these years the raw water is chlorinated in such a way whereby a residual chlorine level of 0.5-1.0 mg/l, is maintained at the outlet of water treatment plant. The adequacy of the current chlorination practice was investigated, at the request of the NPC-500 MWe group during 1990, so that the future requirements of raw water for TAPP-3 and 4, can be met from the expanded SWTP. In this connection experiments on chlorine dose -- residual chlorine relationship and the decay pattern of chlorine with time was carried out in the lake water (with low value of total dissolved solids and total hardness 3 sample at the site. The total bacterial count in the raw water observed to be 10 7 counts/ml originally came down to 10 3 counts/ml at the end of one-hour exposure time to chlorine. It was found that the chlorine demand of the water was around 6 mg/l. In addition Jar test to evaluate the aluminum dose was also carried out. Based on these experiments a chlorine dose of 6 mg/l for one hour contact time was arrived at. The experimental findings were in agreement with the current chlorination practices. (author)

  15. Solvothermal synthesis: a new route for preparing nitrides

    CERN Document Server

    Demazeau, G; Denis, A; Largeteau, A

    2002-01-01

    Solvothermal synthesis appears to be an interesting route for preparing nitrides such as gallium nitride and aluminium nitride, using ammonia as solvent. A nitriding additive is used to perform the reaction and, in the case of gallium nitride, is encapsulated by melt gallium. The syntheses are performed in the temperature range 400-800 deg. C and in the pressure range 100-200 MPa. The synthesized powders are characterized by x-ray diffraction and scanning electron microscopy. Finely divided gallium nitride GaN and aluminium nitride AlN, both with wurtzite-type structure, can be obtained by this route.

  16. Porous silicon technology for integrated microsystems

    Science.gov (United States)

    Wallner, Jin Zheng

    With the development of micro systems, there is an increasing demand for integrable porous materials. In addition to those conventional applications, such as filtration, wicking, and insulating, many new micro devices, including micro reactors, sensors, actuators, and optical components, can benefit from porous materials. Conventional porous materials, such as ceramics and polymers, however, cannot meet the challenges posed by micro systems, due to their incompatibility with standard micro-fabrication processes. In an effort to produce porous materials that can be used in micro systems, porous silicon (PS) generated by anodization of single crystalline silicon has been investigated. In this work, the PS formation process has been extensively studied and characterized as a function of substrate type, crystal orientation, doping concentration, current density and surfactant concentration and type. Anodization conditions have been optimized for producing very thick porous silicon layers with uniform pore size, and for obtaining ideal pore morphologies. Three different types of porous silicon materials: meso porous silicon, macro porous silicon with straight pores, and macro porous silicon with tortuous pores, have been successfully produced. Regular pore arrays with controllable pore size in the range of 2mum to 6mum have been demonstrated as well. Localized PS formation has been achieved by using oxide/nitride/polysilicon stack as masking materials, which can withstand anodization in hydrofluoric acid up to twenty hours. A special etching cell with electrolytic liquid backside contact along with two process flows has been developed to enable the fabrication of thick macro porous silicon membranes with though wafer pores. For device assembly, Si-Au and In-Au bonding technologies have been developed. Very low bonding temperature (˜200°C) and thick/soft bonding layers (˜6mum) have been achieved by In-Au bonding technology, which is able to compensate the potentially

  17. Anaerobic biodegradability and toxicity of wastewaters from chlorine and total chlorine-free bleaching of eucalyptus kraft pulps.

    NARCIS (Netherlands)

    Vidal, G.; Soto, M.; Field, J.; Mendez-Pampin, R.; Lema, J.M.

    1997-01-01

    Chlorine bleaching effluents are problematic for anaerobic wastewater treatment due to their high methanogenic toxicity and low biodegradability. Presently, alternative bleaching processes are being introduced, such as elemental chlorine-free (ECF) and total chlorine-free (TCF) bleaching. The

  18. Cathodoluminescence of cubic boron nitride

    International Nuclear Information System (INIS)

    Tkachev, V.D.; Shipilo, V.B.; Zajtsev, A.M.

    1985-01-01

    Three optically active defects are detected in mono- and polycrystal cubic boron nitride (β-BN). Analysis of intensity of temperature dependences, halfwidth and energy shift of 1.76 eV narrow phononless line (center GC-1) makes it possible to interprete the observed cathodoluminescence spectra an optical analog of the Moessbaner effect. Comparison of the obtained results with the known data for diamond monocrystals makes it possible to suggest that the detected center GC-1 is a nitrogen vacancy . The conclusion, concerning the Moessbauer optical spectra application, is made to analyze structural perfection of β-BN crystal lattice

  19. Surface analysis in steel nitrides by using Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Figueiredo, R.S. de.

    1991-07-01

    The formation of iron nitride layer at low temperatures, 600-700 K, by Moessbauer spectroscopy is studied. These layers were obtained basically through two different processes: ion nitriding and ammonia gas nitriding. A preliminary study about post-discharge nitriding was made using discharge in hollow cathode as well as microwave excitation. The assembly of these chambers is also described. The analysis of the nitrided samples was done by CEMS and CXMS, aided by optical microscopy, and the CEMS and CXMS detectors were constructed by ourselves. We also made a brief study about these detectors, testing as acetone as the mixture 80% He+10% C H 4 as detection gases for the use of CEMS. The surface analysis of the samples showed that in the ammonia gas process nitriding the nitrided layer starts by the superficial formation of an iron nitride rich nitrogen. By thermal evolution this nitride promotes the diffusion of nitrogen and the formation of other more stable nitrides. (author)

  20. Simple process to fabricate nitride alloy powders

    International Nuclear Information System (INIS)

    Yang, Jae Ho; Kim, Dong-Joo; Kim, Keon Sik; Rhee, Young Woo; Oh, Jang-Soo; Kim, Jong Hun; Koo, Yang Hyun

    2013-01-01

    Uranium mono-nitride (UN) is considered as a fuel material [1] for accident-tolerant fuel to compensate for the loss of fissile fuel material caused by adopting a thickened cladding such as SiC composites. Uranium nitride powders can be fabricated by a carbothermic reduction of the oxide powders, or the nitriding of metal uranium. Among them, a direct nitriding process of metal is more attractive because it has advantages in the mass production of high-purity powders and the reusing of expensive 15 N 2 gas. However, since metal uranium is usually fabricated in the form of bulk ingots, it has a drawback in the fabrication of fine powders. The Korea Atomic Energy Research Institute (KAERI) has a centrifugal atomisation technique to fabricate uranium and uranium alloy powders. In this study, a simple reaction method was tested to fabricate nitride fuel powders directly from uranium metal alloy powders. Spherical powder and flake of uranium metal alloys were fabricated using a centrifugal atomisation method. The nitride powders were obtained by thermal treating the metal particles under nitrogen containing gas. The phase and morphology evolutions of powders were investigated during the nitriding process. A phase analysis of nitride powders was also part of the present work. KAERI has developed the centrifugal rotating disk atomisation process to fabricate spherical uranium metal alloy powders which are used as advanced fuel materials for research reactors. The rotating disk atomisation system involves the tasks of melting, atomising, and collecting. A nozzle in the bottom of melting crucible introduces melt at the center of a spinning disk. The centrifugal force carries the melt to the edge of the disk and throws the melt off the edge. Size and shape of droplets can be controlled by changing the nozzle size, the disk diameter and disk speed independently or simultaneously. By adjusting the processing parameters of the centrifugal atomiser, a spherical and flake shape

  1. Chlorine demand and residual chlorine decay kinetics of Kali river water at Kaiga project area

    International Nuclear Information System (INIS)

    Krishna Bhat, D.; Prakash, T.R.; Thimme Gowda, B.; Sherigara, B.S.; Khader, A.M.A.

    1995-01-01

    The nuclear power plant at Kaiga would use Kali river water for condenser cooling. This necessitated studies on the chemistry of chlorination such as chlorine demand, kinetics of chlorination and other water characteristics aimed at obtaining base line data. The study revealed significant seasonal variation of chlorine demand ranging from 0.5 ppm to 1.7 ppm (3.0 ppm dose, 30 min contact time) and total consumption of 5.0 ppm (10.0 ppm dose, 48 hours contact time). The reaction follows first order kinetics in chlorine. High correlation of chlorine demand with chlorophyll a, suspended matter, turbidity, silica, nitrite, phosphate and sulphate indicated that chlorine demand is greatly influenced by water quality. (author). 3 refs., 1 tab

  2. Microstructural Characterization of Low Temperature Gas Nitrided Martensitic Stainless Steel

    DEFF Research Database (Denmark)

    Fernandes, Frederico Augusto Pires; Christiansen, Thomas Lundin; Somers, Marcel A. J.

    2015-01-01

    The present work presents microstructural investigations of the surface zone of low temperature gas nitrided precipitation hardening martensitic stainless steel AISI 630. Grazing incidence X-ray diffraction was applied to investigate the present phases after successive removal of very thin sections...... of the sample surface. The development of epsilon nitride, expanded austenite and expanded martensite resulted from the low temperature nitriding treatments. The microstructural features, hardness and phase composition are discussed with emphasis on the influence of nitriding duration and nitriding potential....

  3. Effectiveness of Chlorinated Water, Sodium Hypochlorite, Sodium ...

    African Journals Online (AJOL)

    This study evaluated the efficacy of chlorinated water, sodium hypochlorite solution, sodium chloride solution and sterile distilled water in eliminating pathogenic bacteria on the surfaces of raw vegetables. Lettuce vegetables were dipped in different concentrations of chlorinated water, sodium hypochlorite solution, sodium ...

  4. Monitoring chlorination practices during operation at TAPS

    International Nuclear Information System (INIS)

    Sriraman, A.K.; Wani, B.N.; Gokhale, A.S.; Yuvaraju, B.

    1995-01-01

    Chlorination of cooling waters is aimed at the condenser surfaces to minimize the biogrowth, while the residual oxidants in the effluents are negligible. This paper describes the fulfillment of the above criteria, as observed during the monitoring of chlorination practices at Tarapur Atomic Power Station (TAPS) during 1990. (author). 4 refs., 2 tabs

  5. Elements from chlorine to calcium nuclear reactions

    CERN Document Server

    Kunz, Wunibald

    1968-01-01

    Nuclear Tables: Part II Nuclear Reactions, Volume 3: The Elements from Chlorine to Calcium contains tabulations of the nuclear reaction values of elements chlorine, argon, potassium, and calcium. These tabulations provide the calculated Q-values of the elements and their isotopes. This book will be of value to general chemistry researchers.

  6. The Synthesis of Carbon Nanomaterials using Chlorinated ...

    African Journals Online (AJOL)

    The effect of chlorine on the morphology of carbon nanotubes (CNTs) prepared from a Fe-Co/CaCO3 catalyst was investigated using chlorobenzene (CB), dichlorobenzene (DCB), trichlorobenzene (TCB), dichloroethane (DCE), trichloroethane (TCE) and tetrachloroethane (TTCE) as chlorine sources using a catalytic ...

  7. Microstructures of group III-nitrides after implantation with gallium

    International Nuclear Information System (INIS)

    Kench, P.J.

    2001-05-01

    High doses of gallium have been implanted into layers of aluminium nitride (AIN), indium nitride (InN) and amorphous silicon nitride (a-SiN x ) in an attempt to bond gallium with nitrogen and form binary or ternary alloys. The microstructure of the resultant layers have been characterised using, principally, transmission electron microscopy and X-ray photoelectron spectroscopy. The implantation of a high dose of Ga ions into AIN was successful in synthesising a GaN/GaAlN compound. The resultant layers were largely uniform but contained aluminium precipitates near the surface. These precipitates were pure Al and were most common in the region associated with the maximum Ga concentration. Deconvolution of X-ray photoelectron spectroscopy peaks indicated that Ga existed in a number of chemical states, including the nitride. Electron diffraction patterns from the implanted layers were closely indexed to both AIN and GaN. A further N implant was used to reduce the concentration of the aluminium precipitates and increase the concentration of GaN bonds. The yield of Ga-N bonds dramatically increased and a reduction in the concentration of Al precipitates was observed. Laser and thermal annealing was performed on the implanted AIN substrates. The near surface regions of the implanted specimens appeared to free of precipitates and bubbles. Laser annealing did have a noticeable effect on the electrical and optical properties of the layers. After laser annealing the conductivity of the Ga implanted layer was lower, indicating that the quality of the material had improved. PL measurements showed that a new PL peak at 2.6 eV appeared after laser annealing. It has been found that implanting InN with gallium can yield Ga-N bonds. However, Ga implants into InN were not as successful at synthesising GaN compounds as those by implanting Ga into AIN, due to the low thermal stability of InN. The implanted InN layers were very irregular and contained large indium precipitates and

  8. Internal chlorination of Ni-Cr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Berztiss, D.; Hennesen, K.; Grabke, H.J. [Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany)

    1998-12-31

    In contrast to internal oxidation, sulfidation and carburization, very little information is available regarding internal chlorination, especially diffusion of chlorine in metallic alloys. This paper describes results of experiments on Ni-Cr alloys (<10 wt% Cr) exposed in an atmosphere containing radioactive HCl. The diffusion of chlorine in the alloy can be determined by measurement of residual {beta}-activity from the sample surface. Successively thin layers (0.5-10 {mu}m) of the alloy were removed by lapping and the surface activity was measured to obtain a depth profile. Both single and polycrystalline materials were tested. Through this work it should be determined if there is in fact solubility and diffusion of chlorine in Ni-based alloys as some authors have proposed or if the ingress of chlorine is mainly a grain boundary phenomenon. (orig.)

  9. Chlorine signal attenuation in concrete.

    Science.gov (United States)

    Naqvi, A A; Maslehuddin, M; Ur-Rehman, Khateeb; Al-Amoudi, O S B

    2015-11-01

    The intensity of prompt gamma-ray was measured at various depths from chlorine-contaminated silica fume (SF) concrete slab concrete specimens using portable neutron generator-based prompt gamma-ray setup. The intensity of 6.11MeV chloride gamma-rays was measured from the chloride contaminated slab at distance of 15.25, 20.25, 25.25, 30.25 and 35.25cm from neutron target in a SF cement concrete slab specimens. Due to attenuation of thermal neutron flux and emitted gamma-ray intensity in SF cement concrete at various depths, the measured intensity of chlorine gamma-rays decreases non-linearly with increasing depth in concrete. A good agreement was noted between the experimental results and the results of Monte Carlo simulation. This study has provided useful experimental data for evaluating the chloride contamination in the SF concrete utilizing gamma-ray attenuation method. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Minimization of zirconium chlorinator residues

    International Nuclear Information System (INIS)

    Green, G.K.; Harbuck, D.D.

    1995-01-01

    Zirconium chlorinator residues contain an array of rare earths, scandium, unreacted coke, and radioactive thorium and radium. Because of the radioactivity, the residues must be disposed in special waste containment facilities. As these sites become more congested, and with stricter environmental regulations, disposal of large volumes of wastes may become more difficult. To reduce the mass of disposed material, the US Bureau of Mines (USBM) developed technology to recover rare earths, thorium and radium, and unreacted coke from these residues. This technology employs an HCl leach to solubilize over 99% of the scandium and thorium, and over 90% of the rare earths. The leach liquor is processed through several solvent extraction stages to selectively recover scandium, thorium, and rare earths. The leach residue is further leached with an organic acid to solubilize radium, thus allowing unreacted coke to be recycled to the chlorinator. The thorium and radium waste products, which comprise only 2.1% of the original residue mass, can then be sent to the radioactive waste facility

  11. Radiochemical analysis of chlorine-36

    International Nuclear Information System (INIS)

    Rodriguez, M.; Pina, G.; Lara, E.

    2006-01-01

    The radioactive chlorine isotope, 36 Cl, decays with a half-life of 3x10 5 years by emitting a beta particle (98 %) and by electron capture. The aim of this paper is to propose a radiochemical separation method of 36 Cl from the other beta-gamma emitters present in low and medium radioactive wastes such as spent ion exchange resins and evaporator concentrates, that arise from Nuclear Power Plants and particularly in the wastes that come from decommissioning activities of graphite reactors, in order to provide data for 36 Cl inventory calculations. The separation method proposed is based on an oxidation technique where chlorine is trapped by NaOH. 36 Cl beta emissions are measured by liquid scintillation counting by the dual label technique in order to avoid the contamination produced by 14 C which is also trapped by NaOH and which is the main contaminant present in graphite samples. The sensitivity of this method is sufficient to achieve the needed thresholds for the radiological characterization of the radioactive materials to which this method can be applied. (author)

  12. New Routes to Lanthanide and Actinide Nitrides

    Energy Technology Data Exchange (ETDEWEB)

    Butt, D.P.; Jaques, B.J.; Osterberg, D.D. [Boise State University, 1910 University Dr., Boise, Idaho 83725-2075 (United States); Marx, B.M. [Concurrent Technologies Corporation, Johnstown, PA (United States); Callahan, P.G. [Carnegie Mellon University, Pittsburgh, PA (United States); Hamdy, A.S. [Central Metallurgical R and D Institute, Helwan, Cairo (Egypt)

    2009-06-15

    The future of nuclear energy in the U.S. and its expansion worldwide depends greatly on our ability to reduce the levels of high level waste to minimal levels, while maintaining proliferation resistance. Implicit in the so-called advanced fuel cycle is the need for higher levels of fuel burn-up and consequential use of complex nuclear fuels comprised of fissile materials such as Pu, Am, Np, and Cm. Advanced nitride fuels comprised ternary and quaternary mixtures of uranium and these actinides have been considered for applications in advanced power plants, but there remain many processing challenges as well as necessary qualification testing. In this presentation, the advantages and disadvantages of nitride fuels are discussed. Methods of synthesizing the raw materials and sintering of fuels are described including a discussion of novel, low cost routes to nitrides that have the potential for reducing the cost and footprint of a fuel processing plant. Phase pure nitrides were synthesized via four primary methods; reactive milling metal flakes in nitrogen at room temperature, directly nitriding metal flakes in a pure nitrogen atmosphere, hydriding metal flakes prior to nitridation, and carbo-thermically reducing the metal oxide and carbon mixture prior to nitridation. In the present study, the sintering of UN, DyN, and their solid solutions (U{sub x}, Dy{sub 1-x}) (x = 1 to 0.7) were also studied. (authors)

  13. Titanium nitride coatings synthesized by IPD method with eliminated current oscillations

    Directory of Open Access Journals (Sweden)

    Chodun Rafał

    2016-09-01

    Full Text Available This paper presents the effects of elimination of current oscillations within the coaxial plasma accelerator during IPD deposition process on the morphology, phase structure and properties of synthesized TiN coatings. Current observations of waveforms have been made by use of an oscilloscope. As a test material for experiments, titanium nitride TiN coatings synthesized on silicon and high-speed steel substrates were used. The coatings morphology, phase composition and wear resistance properties were determined. The character of current waveforms in the plasma accelerator electric circuit plays a crucial role during the coatings synthesis process. Elimination of the current oscillations leads to obtaining an ultrafine grained structure of titanium nitride coatings and to disappearance of the tendency to structure columnarization. The coatings obtained during processes of a non-oscillating character are distinguished by better wear-resistance properties.

  14. Nano Indentation Inspection of the Mechanical Properties of Gold Nitride Thin Films

    Directory of Open Access Journals (Sweden)

    Armen Verdyan

    2007-10-01

    Full Text Available The morphology and the local mechanical properties of gold nitride thin films were studied by atomic force microscope (AFM. Gold nitride films were deposited for the first time on silicon substrate without any buffer layer at room temperature by reactive pulsed laser ablation deposition (RPLD. The films were fabricated on (100 Si wafers by RPLD technique in which KrF excimer laser was used to ablate a gold target in N2 atmosphere (0.1 GPa-100 Pa and ambient temperature. Scanning electron microscopy (SEM and atomic force microscopy inspections showed that the films were flat plane with rms roughness in the range of 35.1 nm-3.6 nm, depending on the deposition pressure. Rutherford backscattering spectrometry (RBS and energy dispersion spectroscopy (EDS used to detect the nitrogen concentration in the films, have revealed a composition close to Au3N. The film

  15. Room-temperature low-voltage electroluminescence in amorphous carbon nitride thin films

    Science.gov (United States)

    Reyes, R.; Legnani, C.; Ribeiro Pinto, P. M.; Cremona, M.; de Araújo, P. J. G.; Achete, C. A.

    2003-06-01

    White-blue electroluminescent emission with a voltage bias less than 10 V was achieved in rf sputter-deposited amorphous carbon nitride (a-CN) and amorphous silicon carbon nitride (a-SiCN) thin-film-based devices. The heterojunction structures of these devices consist of: Indium tin oxide (ITO), used as a transparent anode; amorphous carbon film as an emission layer, and aluminum as a cathode. The thickness of the carbon films was about 250 Å. In all of the produced diodes, a stable visible emission peaked around 475 nm is observed at room temperature and the emission intensity increases with the current density. For an applied voltage of 14 V, the luminance was about 3 mCd/m2. The electroluminescent properties of the two devices are discussed and compared.

  16. Superstructure of self-aligned hexagonal GaN nanorods formed on nitrided Si(111) surface

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Praveen; Tuteja, Mohit; Kesaria, Manoj; Waghmare, U. V.; Shivaprasad, S. M. [Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064 (India)

    2012-09-24

    We present here the spontaneous formation of catalyst-free, self-aligned crystalline (wurtzite) nanorods on Si(111) surfaces modified by surface nitridation. Nanorods grown by molecular beam epitaxy on bare Si(111) and non-stoichiometric silicon nitride interface are found to be single crystalline but disoriented. Those grown on single crystalline Si{sub 3}N{sub 4} intermediate layer are highly dense c-oriented hexagonal shaped nanorods. The morphology and the self-assembly of the nanorods shows an ordered epitaxial hexagonal superstructure, suggesting that they are nucleated at screw dislocations at the interface and grow spirally in the c-direction. The aligned nanorod assembly shows high-quality structural and optical emission properties.

  17. Corrosion resistant surface for vanadium nitride and hafnium nitride layers as function of grain size

    Science.gov (United States)

    Escobar, C. A.; Caicedo, J. C.; Aperador, W.

    2014-01-01

    In this research it was studied vanadium nitride (VN) and hafnium nitride (HfN) film, which were deposited onto silicon (Si (100)) and AISI 4140 steel substrates via r.f. magnetron sputtering technique in Ar/N2 atmosphere with purity at 99.99% for both V and Hf metallic targets. Both films were approximately 1.2±0.1 μm thick. The crystallography structures that were evaluated via X-ray diffraction analysis (XRD) showed preferential orientations in the Bragg planes VN (200) and HfN (111). The chemical compositions for both films were characterized by EDX. Atomic Force Microscopy (AFM) was used to study the morphology; the results reveal grain sizes of 78±2 nm for VN and 58±2 nm for HfN and roughness values of 4.2±0.1 nm for VN and 1.5±0.1 nm for HfN films. The electrochemical performance in VN and HfN films deposited onto steel 4140 were studied by Tafel polarization curves and impedance spectroscopy methods (EIS) under contact with sodium chloride at 3.5 wt% solution, therefore, it was found that the corrosion rate decreased about 95% in VN and 99% for HfN films in relation to uncoated 4140 steel, thus demonstrating, the protecting effect of VN and HfN films under a corrosive environment as function of morphological characteristics (grain size). VN(grain size)=78±2.0 nm, VN(roughness)=4.2±0.1 nm, VN(corrosion rate)=40.87 μmy. HfN(grain size)=58±2.0 nm, HfN(roughness)=1.5±0.1 nm, HfN(corrosion rate)=0.205 μmy. It was possible to analyze that films with larger grain size, can be observed smaller grain boundary thus generating a higher corrosion rate, therefore, in this work it was found that the HfN layer has better corrosion resistance (low corrosion rate) in relation to VN film which presents a larger grain size, indicating that the low grain boundary in (VN films) does not restrict movement of the Cl- ion and in this way the corrosion rate increases dramatically.

  18. Chlorination of irradiated polyethylene single crystals

    International Nuclear Information System (INIS)

    Grimm, H.J.

    1978-01-01

    The chlorination of electron beam-irradiation polyethylene (PE) single crystals was studied for a range of irradiation doses, temperatures, and chlorine interaction times. The results presented show that PE chlorination was quite extensive, even in unirradiated PE single crystals at 25 0 C in the dark. Electron Spin Resonance (ESR, EPR) was used in this study in order to determine the alkyl radical concentration, decay constant, and diffusivity for (unchlorinated) specimens. An alkyl radical diffusivity D/sub a/ = 1.6 x 10 -17 cm 2 /sec at 25 0 C was estimated from ESR data and alkyl radical migration as one-dimensional unsteady-state diffusion process. In irradiated PE, chlorination occurred mainly via chain reactions which were initiated by the irradiation-produced free radicals. Chlorine content values were determined by X-ray Energy Spectroscopy (XES). It was found that the magnitude of the chlorine uptake increased with increasing dose, and decreased with decreasing temperature at constant dose. Otherwise the observed PE chlorination phenomena was quite similar for all of the doses and temperatures studied here, consisting of a two step mechanism: a fast uptake which occurred between time tCl 2 = 0 - 5 minutes and a slower, approximately first-order rate of uptake which occurred between times tCl 2 = 5 - 120 minutes. Chlorination was essentially complete by time tCl 2 = 120 minutes. The rapid uptake probably occurred in the amorphous surface zones where Cl 2 is relatively high and the second, slower step was probably attributable to Cl 2 diffusion into the crystalline regions and subsequent chlorination there. Inasmuch as the PE density decreases with increasing dose (for 1-600 Mrad), Cl 2 diffusivity was enhanced, resulting in higher chlorine uptake values at higher doses

  19. Integrated GaN photonic circuits on silicon (100) for second harmonic generation

    OpenAIRE

    Xiong, Chi; Pernice, Wolfram; Ryu, Kevin K.; Schuck, Carsten; Fong, King Y.; Palacios, Tomas; Tang, Hong X.

    2014-01-01

    We demonstrate second order optical nonlinearity in a silicon architecture through heterogeneous integration of single-crystalline gallium nitride (GaN) on silicon (100) substrates. By engineering GaN microrings for dual resonance around 1560 nm and 780 nm, we achieve efficient, tunable second harmonic generation at 780 nm. The \\{chi}(2) nonlinear susceptibility is measured to be as high as 16 plus minus 7 pm/V. Because GaN has a wideband transparency window covering ultraviolet, visible and ...

  20. Silicon technology-based micro-systems for atomic force microscopy/photon scanning tunnelling microscopy.

    Science.gov (United States)

    Gall-Borrut, P; Belier, B; Falgayrettes, P; Castagne, M; Bergaud, C; Temple-Boyer, P

    2001-04-01

    We developed silicon nitride cantilevers integrating a probe tip and a wave guide that is prolonged on the silicon holder with one or two guides. A micro-system is bonded to a photodetector. The resulting hybrid system enables us to obtain simultaneously topographic and optical near-field images. Examples of images obtained on a longitudinal cross-section of an optical fibre are shown.